<?xml version="1.0" encoding="UTF-8"?>

<!--XBRL Document Created with Wdesk from Workiva-->
<!--Copyright 2022 Workiva-->
<!--r:0e4aa268-3b52-4654-a163-baa048d5aba8,g:d1fa831d-de0d-46fe-abb0-d4dcb1cb1742-->
<link:linkbase xmlns:link="http://www.xbrl.org/2003/linkbase" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xbrldt="http://xbrl.org/2005/xbrldt" xsi:schemaLocation="http://www.xbrl.org/2003/linkbase http://www.xbrl.org/2003/xbrl-linkbase-2003-12-31.xsd">
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/all" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#all"/>
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#hypercube-dimension"/>
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-default"/>
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-domain"/>
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/domain-member" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#domain-member"/>
  <link:roleRef roleURI="http://www.westlake.com/role/CoverPage" xlink:type="simple" xlink:href="wlkp-20211231.xsd#CoverPage"/>
  <link:definitionLink xlink:role="http://www.westlake.com/role/CoverPage" xlink:type="extended" id="ib1c03f3b3d5243e3bcdfc118ab5ef790_CoverPage">
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentInformationLineItems_15a3efd6-7d1d-4f72-97a9-ba927e2dd065" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_DocumentInformationLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentType_317b6652-f665-47cf-bf64-dbd1eaf6e89f" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_DocumentType"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_15a3efd6-7d1d-4f72-97a9-ba927e2dd065" xlink:to="loc_dei_DocumentType_317b6652-f665-47cf-bf64-dbd1eaf6e89f" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentAnnualReport_681264bd-0e9b-4f87-92d5-554619d7465d" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_DocumentAnnualReport"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_15a3efd6-7d1d-4f72-97a9-ba927e2dd065" xlink:to="loc_dei_DocumentAnnualReport_681264bd-0e9b-4f87-92d5-554619d7465d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentPeriodEndDate_d2f5fd46-4180-4b03-bb56-846dacfca76d" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_DocumentPeriodEndDate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_15a3efd6-7d1d-4f72-97a9-ba927e2dd065" xlink:to="loc_dei_DocumentPeriodEndDate_d2f5fd46-4180-4b03-bb56-846dacfca76d" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_CurrentFiscalYearEndDate_75900164-ef36-44d7-bd69-0b7a97b30bf5" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_CurrentFiscalYearEndDate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_15a3efd6-7d1d-4f72-97a9-ba927e2dd065" xlink:to="loc_dei_CurrentFiscalYearEndDate_75900164-ef36-44d7-bd69-0b7a97b30bf5" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentTransitionReport_3bac43d8-cfa8-4b2f-9f2f-d904debf4a90" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_DocumentTransitionReport"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_15a3efd6-7d1d-4f72-97a9-ba927e2dd065" xlink:to="loc_dei_DocumentTransitionReport_3bac43d8-cfa8-4b2f-9f2f-d904debf4a90" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityFileNumber_21e42793-e984-4fea-9361-8414371b8cf0" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_EntityFileNumber"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_15a3efd6-7d1d-4f72-97a9-ba927e2dd065" xlink:to="loc_dei_EntityFileNumber_21e42793-e984-4fea-9361-8414371b8cf0" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityRegistrantName_f8919d24-1d25-41b2-b7ba-56dd6cbfc89c" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_EntityRegistrantName"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_15a3efd6-7d1d-4f72-97a9-ba927e2dd065" xlink:to="loc_dei_EntityRegistrantName_f8919d24-1d25-41b2-b7ba-56dd6cbfc89c" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityIncorporationStateCountryCode_41556242-7889-4a30-9538-5da8518ad39c" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_EntityIncorporationStateCountryCode"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_15a3efd6-7d1d-4f72-97a9-ba927e2dd065" xlink:to="loc_dei_EntityIncorporationStateCountryCode_41556242-7889-4a30-9538-5da8518ad39c" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityTaxIdentificationNumber_d2ec84d4-d219-42c8-b1a9-e62f08d68175" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_EntityTaxIdentificationNumber"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_15a3efd6-7d1d-4f72-97a9-ba927e2dd065" xlink:to="loc_dei_EntityTaxIdentificationNumber_d2ec84d4-d219-42c8-b1a9-e62f08d68175" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressAddressLine1_89f700c9-564a-4c54-83ba-af40955ba2ee" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_EntityAddressAddressLine1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_15a3efd6-7d1d-4f72-97a9-ba927e2dd065" xlink:to="loc_dei_EntityAddressAddressLine1_89f700c9-564a-4c54-83ba-af40955ba2ee" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressAddressLine2_d987cbe1-2ad4-4753-b5b1-7e0093ab8c8d" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_EntityAddressAddressLine2"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_15a3efd6-7d1d-4f72-97a9-ba927e2dd065" xlink:to="loc_dei_EntityAddressAddressLine2_d987cbe1-2ad4-4753-b5b1-7e0093ab8c8d" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressCityOrTown_0039f279-8eb3-4fdf-a63d-684e660f1c95" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_EntityAddressCityOrTown"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_15a3efd6-7d1d-4f72-97a9-ba927e2dd065" xlink:to="loc_dei_EntityAddressCityOrTown_0039f279-8eb3-4fdf-a63d-684e660f1c95" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressPostalZipCode_3afb14fd-2cc0-4624-b004-9456ba651c85" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_EntityAddressPostalZipCode"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_15a3efd6-7d1d-4f72-97a9-ba927e2dd065" xlink:to="loc_dei_EntityAddressPostalZipCode_3afb14fd-2cc0-4624-b004-9456ba651c85" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressStateOrProvince_f70bfbfb-9e58-40cc-bc26-e26a01774cc5" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_EntityAddressStateOrProvince"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_15a3efd6-7d1d-4f72-97a9-ba927e2dd065" xlink:to="loc_dei_EntityAddressStateOrProvince_f70bfbfb-9e58-40cc-bc26-e26a01774cc5" xlink:type="arc" order="13"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_CityAreaCode_9bbd492e-19ff-4aca-becd-789608748353" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_CityAreaCode"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_15a3efd6-7d1d-4f72-97a9-ba927e2dd065" xlink:to="loc_dei_CityAreaCode_9bbd492e-19ff-4aca-becd-789608748353" xlink:type="arc" order="14"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_LocalPhoneNumber_f1f56ac9-e033-4a64-852b-fe0584e3da96" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_LocalPhoneNumber"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_15a3efd6-7d1d-4f72-97a9-ba927e2dd065" xlink:to="loc_dei_LocalPhoneNumber_f1f56ac9-e033-4a64-852b-fe0584e3da96" xlink:type="arc" order="15"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_Security12bTitle_598401a1-73f2-424a-8a56-74abfc255ed6" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_Security12bTitle"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_15a3efd6-7d1d-4f72-97a9-ba927e2dd065" xlink:to="loc_dei_Security12bTitle_598401a1-73f2-424a-8a56-74abfc255ed6" xlink:type="arc" order="16"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_TradingSymbol_2b65324c-bf67-416c-964d-10a7df8643ca" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_TradingSymbol"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_15a3efd6-7d1d-4f72-97a9-ba927e2dd065" xlink:to="loc_dei_TradingSymbol_2b65324c-bf67-416c-964d-10a7df8643ca" xlink:type="arc" order="17"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_SecurityExchangeName_30ebe4fd-6389-431b-927b-6d1991f381d1" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_SecurityExchangeName"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_15a3efd6-7d1d-4f72-97a9-ba927e2dd065" xlink:to="loc_dei_SecurityExchangeName_30ebe4fd-6389-431b-927b-6d1991f381d1" xlink:type="arc" order="18"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityWellKnownSeasonedIssuer_1e8941b3-516a-46ac-92d6-cd709d39d684" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_EntityWellKnownSeasonedIssuer"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_15a3efd6-7d1d-4f72-97a9-ba927e2dd065" xlink:to="loc_dei_EntityWellKnownSeasonedIssuer_1e8941b3-516a-46ac-92d6-cd709d39d684" xlink:type="arc" order="19"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityVoluntaryFilers_aff39bbf-d65b-49eb-8eda-2b62828307f9" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_EntityVoluntaryFilers"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_15a3efd6-7d1d-4f72-97a9-ba927e2dd065" xlink:to="loc_dei_EntityVoluntaryFilers_aff39bbf-d65b-49eb-8eda-2b62828307f9" xlink:type="arc" order="20"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityCurrentReportingStatus_8d2fd51b-66ce-4b35-9cf8-ddeb5342ddfc" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_EntityCurrentReportingStatus"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_15a3efd6-7d1d-4f72-97a9-ba927e2dd065" xlink:to="loc_dei_EntityCurrentReportingStatus_8d2fd51b-66ce-4b35-9cf8-ddeb5342ddfc" xlink:type="arc" order="21"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityInteractiveDataCurrent_d4ab3eda-f5c1-4230-bd1e-b4cf23aac457" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_EntityInteractiveDataCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_15a3efd6-7d1d-4f72-97a9-ba927e2dd065" xlink:to="loc_dei_EntityInteractiveDataCurrent_d4ab3eda-f5c1-4230-bd1e-b4cf23aac457" xlink:type="arc" order="22"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityFilerCategory_17862d27-9268-48cc-ac86-1647113db3dd" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_EntityFilerCategory"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_15a3efd6-7d1d-4f72-97a9-ba927e2dd065" xlink:to="loc_dei_EntityFilerCategory_17862d27-9268-48cc-ac86-1647113db3dd" xlink:type="arc" order="23"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityEmergingGrowthCompany_2a557532-45d5-434c-b226-4a6247ef99cd" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_EntityEmergingGrowthCompany"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_15a3efd6-7d1d-4f72-97a9-ba927e2dd065" xlink:to="loc_dei_EntityEmergingGrowthCompany_2a557532-45d5-434c-b226-4a6247ef99cd" xlink:type="arc" order="24"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntitySmallBusiness_11759329-292c-4141-9e5e-d120e87a069d" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_EntitySmallBusiness"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_15a3efd6-7d1d-4f72-97a9-ba927e2dd065" xlink:to="loc_dei_EntitySmallBusiness_11759329-292c-4141-9e5e-d120e87a069d" xlink:type="arc" order="25"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_IcfrAuditorAttestationFlag_d2ae837c-86ac-4995-9d9b-c0db1e616145" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_IcfrAuditorAttestationFlag"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_15a3efd6-7d1d-4f72-97a9-ba927e2dd065" xlink:to="loc_dei_IcfrAuditorAttestationFlag_d2ae837c-86ac-4995-9d9b-c0db1e616145" xlink:type="arc" order="26"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityShellCompany_a6f1d030-00cc-4b48-b73b-17091bdcc5ca" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_EntityShellCompany"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_15a3efd6-7d1d-4f72-97a9-ba927e2dd065" xlink:to="loc_dei_EntityShellCompany_a6f1d030-00cc-4b48-b73b-17091bdcc5ca" xlink:type="arc" order="27"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityPublicFloat_d0397610-19fb-4f26-ae1f-a7ce0475acb6" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_EntityPublicFloat"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_15a3efd6-7d1d-4f72-97a9-ba927e2dd065" xlink:to="loc_dei_EntityPublicFloat_d0397610-19fb-4f26-ae1f-a7ce0475acb6" xlink:type="arc" order="28"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityCommonStockSharesOutstanding_8404c644-ecd9-4923-a9f9-7b1b2249223a" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_EntityCommonStockSharesOutstanding"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_15a3efd6-7d1d-4f72-97a9-ba927e2dd065" xlink:to="loc_dei_EntityCommonStockSharesOutstanding_8404c644-ecd9-4923-a9f9-7b1b2249223a" xlink:type="arc" order="29"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityCentralIndexKey_91e55678-58f3-4c0f-a33e-6640e27102b5" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_EntityCentralIndexKey"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_15a3efd6-7d1d-4f72-97a9-ba927e2dd065" xlink:to="loc_dei_EntityCentralIndexKey_91e55678-58f3-4c0f-a33e-6640e27102b5" xlink:type="arc" order="30"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentFiscalYearFocus_e111636f-5484-4cd9-b4d6-d4c611e5fbbe" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_DocumentFiscalYearFocus"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_15a3efd6-7d1d-4f72-97a9-ba927e2dd065" xlink:to="loc_dei_DocumentFiscalYearFocus_e111636f-5484-4cd9-b4d6-d4c611e5fbbe" xlink:type="arc" order="31"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentFiscalPeriodFocus_e2d23612-4489-4e32-864b-9e0977286b58" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_DocumentFiscalPeriodFocus"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_15a3efd6-7d1d-4f72-97a9-ba927e2dd065" xlink:to="loc_dei_DocumentFiscalPeriodFocus_e2d23612-4489-4e32-864b-9e0977286b58" xlink:type="arc" order="32"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_AmendmentFlag_810a3769-1e6d-4e9c-b71e-58cfb9da5ac9" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_AmendmentFlag"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_15a3efd6-7d1d-4f72-97a9-ba927e2dd065" xlink:to="loc_dei_AmendmentFlag_810a3769-1e6d-4e9c-b71e-58cfb9da5ac9" xlink:type="arc" order="33"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentInformationTable_26c9bf82-184e-47a9-9a1c-61f244016d35" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_DocumentInformationTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_dei_DocumentInformationLineItems_15a3efd6-7d1d-4f72-97a9-ba927e2dd065" xlink:to="loc_dei_DocumentInformationTable_26c9bf82-184e-47a9-9a1c-61f244016d35" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementClassOfStockAxis_ea4d201e-ce8b-4606-8815-ce7efcbd4a5f" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StatementClassOfStockAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_dei_DocumentInformationTable_26c9bf82-184e-47a9-9a1c-61f244016d35" xlink:to="loc_us-gaap_StatementClassOfStockAxis_ea4d201e-ce8b-4606-8815-ce7efcbd4a5f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockDomain_ea4d201e-ce8b-4606-8815-ce7efcbd4a5f_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ClassOfStockDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementClassOfStockAxis_ea4d201e-ce8b-4606-8815-ce7efcbd4a5f" xlink:to="loc_us-gaap_ClassOfStockDomain_ea4d201e-ce8b-4606-8815-ce7efcbd4a5f_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockDomain_ba7f5ee7-6d67-4131-a860-fb48a42b0bd0" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ClassOfStockDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementClassOfStockAxis_ea4d201e-ce8b-4606-8815-ce7efcbd4a5f" xlink:to="loc_us-gaap_ClassOfStockDomain_ba7f5ee7-6d67-4131-a860-fb48a42b0bd0" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_wlkp_CommonUnitsMember_c4265de8-c52b-4ab7-9b17-2905fe09846c" xlink:href="wlkp-20211231.xsd#wlkp_CommonUnitsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_ba7f5ee7-6d67-4131-a860-fb48a42b0bd0" xlink:to="loc_wlkp_CommonUnitsMember_c4265de8-c52b-4ab7-9b17-2905fe09846c" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_wlkp_SubordinatedUnitsMember_c7e91fa9-72cc-40e7-8785-54e300509048" xlink:href="wlkp-20211231.xsd#wlkp_SubordinatedUnitsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_ba7f5ee7-6d67-4131-a860-fb48a42b0bd0" xlink:to="loc_wlkp_SubordinatedUnitsMember_c7e91fa9-72cc-40e7-8785-54e300509048" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.westlake.com/role/ConsolidatedBalanceSheets" xlink:type="simple" xlink:href="wlkp-20211231.xsd#ConsolidatedBalanceSheets"/>
  <link:definitionLink xlink:role="http://www.westlake.com/role/ConsolidatedBalanceSheets" xlink:type="extended" id="i34b8e045b1734c54adef28675981f99c_ConsolidatedBalanceSheets">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems_91b77d40-3ef1-45b0-84c3-74bb95f83ad8" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StatementLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetsAbstract_eaea107a-e5db-4feb-879a-2534f8b0467c" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AssetsAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_91b77d40-3ef1-45b0-84c3-74bb95f83ad8" xlink:to="loc_us-gaap_AssetsAbstract_eaea107a-e5db-4feb-879a-2534f8b0467c" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetsCurrentAbstract_a9555cc3-04c4-4247-a4e7-f7831cf32fd0" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AssetsCurrentAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_eaea107a-e5db-4feb-879a-2534f8b0467c" xlink:to="loc_us-gaap_AssetsCurrentAbstract_a9555cc3-04c4-4247-a4e7-f7831cf32fd0" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashAndCashEquivalentsAtCarryingValue_ad91e14a-fa73-41bc-b7b2-e3c06544decf" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CashAndCashEquivalentsAtCarryingValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsCurrentAbstract_a9555cc3-04c4-4247-a4e7-f7831cf32fd0" xlink:to="loc_us-gaap_CashAndCashEquivalentsAtCarryingValue_ad91e14a-fa73-41bc-b7b2-e3c06544decf" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_wlkp_ReceivablesunderInvestmentManagementAgreementswithRelatedPartiesCurrent_27c588a9-c8d7-4383-b884-3ed15b78a38c" xlink:href="wlkp-20211231.xsd#wlkp_ReceivablesunderInvestmentManagementAgreementswithRelatedPartiesCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsCurrentAbstract_a9555cc3-04c4-4247-a4e7-f7831cf32fd0" xlink:to="loc_wlkp_ReceivablesunderInvestmentManagementAgreementswithRelatedPartiesCurrent_27c588a9-c8d7-4383-b884-3ed15b78a38c" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountsReceivableRelatedPartiesCurrent_16447205-fca0-4ddb-a20f-4c956107c395" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AccountsReceivableRelatedPartiesCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsCurrentAbstract_a9555cc3-04c4-4247-a4e7-f7831cf32fd0" xlink:to="loc_us-gaap_AccountsReceivableRelatedPartiesCurrent_16447205-fca0-4ddb-a20f-4c956107c395" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountsAndOtherReceivablesNetCurrent_a5ec4bbd-a936-46b9-ae8f-00c6a027a37f" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AccountsAndOtherReceivablesNetCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsCurrentAbstract_a9555cc3-04c4-4247-a4e7-f7831cf32fd0" xlink:to="loc_us-gaap_AccountsAndOtherReceivablesNetCurrent_a5ec4bbd-a936-46b9-ae8f-00c6a027a37f" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InventoryNet_82abe8c2-a183-43a6-aa33-678654ebfb1f" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_InventoryNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsCurrentAbstract_a9555cc3-04c4-4247-a4e7-f7831cf32fd0" xlink:to="loc_us-gaap_InventoryNet_82abe8c2-a183-43a6-aa33-678654ebfb1f" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PrepaidExpenseAndOtherAssetsCurrent_7555a735-8307-404e-9666-af2ffcddf870" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PrepaidExpenseAndOtherAssetsCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsCurrentAbstract_a9555cc3-04c4-4247-a4e7-f7831cf32fd0" xlink:to="loc_us-gaap_PrepaidExpenseAndOtherAssetsCurrent_7555a735-8307-404e-9666-af2ffcddf870" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetsCurrent_836effed-1a9b-4fbd-a04d-78946d68437c" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AssetsCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsCurrentAbstract_a9555cc3-04c4-4247-a4e7-f7831cf32fd0" xlink:to="loc_us-gaap_AssetsCurrent_836effed-1a9b-4fbd-a04d-78946d68437c" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentNet_6e960536-65f6-4886-9e89-52696431b643" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PropertyPlantAndEquipmentNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_eaea107a-e5db-4feb-879a-2534f8b0467c" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentNet_6e960536-65f6-4886-9e89-52696431b643" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Goodwill_876909ac-0f3b-4b4f-9c97-d86a6112cef7" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_Goodwill"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_eaea107a-e5db-4feb-879a-2534f8b0467c" xlink:to="loc_us-gaap_Goodwill_876909ac-0f3b-4b4f-9c97-d86a6112cef7" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredCostsAndOtherAssets_304e62e7-a30e-4fb2-9e1b-e76826483ced" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DeferredCostsAndOtherAssets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_eaea107a-e5db-4feb-879a-2534f8b0467c" xlink:to="loc_us-gaap_DeferredCostsAndOtherAssets_304e62e7-a30e-4fb2-9e1b-e76826483ced" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Assets_2539540f-ae92-4c1a-a1f9-9e54b7777a2e" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_Assets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_eaea107a-e5db-4feb-879a-2534f8b0467c" xlink:to="loc_us-gaap_Assets_2539540f-ae92-4c1a-a1f9-9e54b7777a2e" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_3cbc9313-6662-49f2-961d-c80275f85a9a" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LiabilitiesAndStockholdersEquityAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_91b77d40-3ef1-45b0-84c3-74bb95f83ad8" xlink:to="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_3cbc9313-6662-49f2-961d-c80275f85a9a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesCurrentAbstract_06c5e63a-3a7d-4c2a-bcd7-82517664d1af" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LiabilitiesCurrentAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_3cbc9313-6662-49f2-961d-c80275f85a9a" xlink:to="loc_us-gaap_LiabilitiesCurrentAbstract_06c5e63a-3a7d-4c2a-bcd7-82517664d1af" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountsPayableRelatedPartiesCurrent_cc8296ce-e1d5-4718-bbba-a1ce5f13834a" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AccountsPayableRelatedPartiesCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesCurrentAbstract_06c5e63a-3a7d-4c2a-bcd7-82517664d1af" xlink:to="loc_us-gaap_AccountsPayableRelatedPartiesCurrent_cc8296ce-e1d5-4718-bbba-a1ce5f13834a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountsPayableCurrent_75aee1be-3054-4a91-9659-b8d2b6cf68dd" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AccountsPayableCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesCurrentAbstract_06c5e63a-3a7d-4c2a-bcd7-82517664d1af" xlink:to="loc_us-gaap_AccountsPayableCurrent_75aee1be-3054-4a91-9659-b8d2b6cf68dd" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccruedLiabilitiesCurrent_a8dd0db1-f3ab-4f4d-a184-910c45f879e8" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AccruedLiabilitiesCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesCurrentAbstract_06c5e63a-3a7d-4c2a-bcd7-82517664d1af" xlink:to="loc_us-gaap_AccruedLiabilitiesCurrent_a8dd0db1-f3ab-4f4d-a184-910c45f879e8" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesCurrent_85b4a08b-1b0e-4d43-9569-30c28189172b" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LiabilitiesCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesCurrentAbstract_06c5e63a-3a7d-4c2a-bcd7-82517664d1af" xlink:to="loc_us-gaap_LiabilitiesCurrent_85b4a08b-1b0e-4d43-9569-30c28189172b" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DueToRelatedPartiesNoncurrent_dbe03d78-6e56-40c0-8ccf-157a07176e4b" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DueToRelatedPartiesNoncurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_3cbc9313-6662-49f2-961d-c80275f85a9a" xlink:to="loc_us-gaap_DueToRelatedPartiesNoncurrent_dbe03d78-6e56-40c0-8ccf-157a07176e4b" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredIncomeTaxLiabilitiesNet_f50b2239-c02d-4a1d-9aac-3484aab37d07" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DeferredIncomeTaxLiabilitiesNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_3cbc9313-6662-49f2-961d-c80275f85a9a" xlink:to="loc_us-gaap_DeferredIncomeTaxLiabilitiesNet_f50b2239-c02d-4a1d-9aac-3484aab37d07" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherLiabilitiesNoncurrent_73fbe303-1d8e-48e8-966e-529b0d7a27e5" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherLiabilitiesNoncurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_3cbc9313-6662-49f2-961d-c80275f85a9a" xlink:to="loc_us-gaap_OtherLiabilitiesNoncurrent_73fbe303-1d8e-48e8-966e-529b0d7a27e5" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Liabilities_4131f02f-752a-4cae-b562-d6b331fc5d89" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_Liabilities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_3cbc9313-6662-49f2-961d-c80275f85a9a" xlink:to="loc_us-gaap_Liabilities_4131f02f-752a-4cae-b562-d6b331fc5d89" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommitmentsAndContingencies_fe1cd888-7c84-49a5-9601-3bc9ee526fe9" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CommitmentsAndContingencies"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_3cbc9313-6662-49f2-961d-c80275f85a9a" xlink:to="loc_us-gaap_CommitmentsAndContingencies_fe1cd888-7c84-49a5-9601-3bc9ee526fe9" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquityAbstract_1c5b3173-170e-406e-a64d-65f4235e175d" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StockholdersEquityAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_91b77d40-3ef1-45b0-84c3-74bb95f83ad8" xlink:to="loc_us-gaap_StockholdersEquityAbstract_1c5b3173-170e-406e-a64d-65f4235e175d" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LimitedPartnersCapitalAccount_44b947e8-0e9c-4649-a25c-a636b2867400" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LimitedPartnersCapitalAccount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityAbstract_1c5b3173-170e-406e-a64d-65f4235e175d" xlink:to="loc_us-gaap_LimitedPartnersCapitalAccount_44b947e8-0e9c-4649-a25c-a636b2867400" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GeneralPartnersCapitalAccount_5c7d1fd9-93a5-4646-9520-83db6c162ab7" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_GeneralPartnersCapitalAccount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityAbstract_1c5b3173-170e-406e-a64d-65f4235e175d" xlink:to="loc_us-gaap_GeneralPartnersCapitalAccount_5c7d1fd9-93a5-4646-9520-83db6c162ab7" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PartnersCapital_b9945839-3772-417b-acbd-020fbfabcf54" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PartnersCapital"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityAbstract_1c5b3173-170e-406e-a64d-65f4235e175d" xlink:to="loc_us-gaap_PartnersCapital_b9945839-3772-417b-acbd-020fbfabcf54" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MinorityInterestInLimitedPartnerships_3c4e1391-2b58-4483-9a1f-bf23669521fc" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_MinorityInterestInLimitedPartnerships"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityAbstract_1c5b3173-170e-406e-a64d-65f4235e175d" xlink:to="loc_us-gaap_MinorityInterestInLimitedPartnerships_3c4e1391-2b58-4483-9a1f-bf23669521fc" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PartnersCapitalIncludingPortionAttributableToNoncontrollingInterest_8606647d-e0a9-46c0-8cd5-cbb665c50240" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PartnersCapitalIncludingPortionAttributableToNoncontrollingInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityAbstract_1c5b3173-170e-406e-a64d-65f4235e175d" xlink:to="loc_us-gaap_PartnersCapitalIncludingPortionAttributableToNoncontrollingInterest_8606647d-e0a9-46c0-8cd5-cbb665c50240" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesAndStockholdersEquity_015c2c22-937e-443a-8b4f-f4723d32606f" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LiabilitiesAndStockholdersEquity"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityAbstract_1c5b3173-170e-406e-a64d-65f4235e175d" xlink:to="loc_us-gaap_LiabilitiesAndStockholdersEquity_015c2c22-937e-443a-8b4f-f4723d32606f" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LimitedPartnersCapitalAccountUnitsIssued_1d3f980e-450a-49ef-b37b-1ccf9ecdce04" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LimitedPartnersCapitalAccountUnitsIssued"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_91b77d40-3ef1-45b0-84c3-74bb95f83ad8" xlink:to="loc_us-gaap_LimitedPartnersCapitalAccountUnitsIssued_1d3f980e-450a-49ef-b37b-1ccf9ecdce04" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementTable_6de4ff7c-b07b-4acf-8531-a87e5eff2376" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StatementTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_91b77d40-3ef1-45b0-84c3-74bb95f83ad8" xlink:to="loc_us-gaap_StatementTable_6de4ff7c-b07b-4acf-8531-a87e5eff2376" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PartnerTypeOfPartnersCapitalAccountAxis_f7a2ce1c-1bed-4284-8558-192c6a64156f" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PartnerTypeOfPartnersCapitalAccountAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_6de4ff7c-b07b-4acf-8531-a87e5eff2376" xlink:to="loc_us-gaap_PartnerTypeOfPartnersCapitalAccountAxis_f7a2ce1c-1bed-4284-8558-192c6a64156f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PartnerTypeOfPartnersCapitalAccountNameDomain_f7a2ce1c-1bed-4284-8558-192c6a64156f_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PartnerTypeOfPartnersCapitalAccountNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_PartnerTypeOfPartnersCapitalAccountAxis_f7a2ce1c-1bed-4284-8558-192c6a64156f" xlink:to="loc_us-gaap_PartnerTypeOfPartnersCapitalAccountNameDomain_f7a2ce1c-1bed-4284-8558-192c6a64156f_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PartnerTypeOfPartnersCapitalAccountNameDomain_cdceabaa-2cd3-489c-afe6-46445825a522" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PartnerTypeOfPartnersCapitalAccountNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_PartnerTypeOfPartnersCapitalAccountAxis_f7a2ce1c-1bed-4284-8558-192c6a64156f" xlink:to="loc_us-gaap_PartnerTypeOfPartnersCapitalAccountNameDomain_cdceabaa-2cd3-489c-afe6-46445825a522" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LimitedPartnerMember_0337c488-4bbe-423a-8bc7-0438ac6aab9e" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LimitedPartnerMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PartnerTypeOfPartnersCapitalAccountNameDomain_cdceabaa-2cd3-489c-afe6-46445825a522" xlink:to="loc_us-gaap_LimitedPartnerMember_0337c488-4bbe-423a-8bc7-0438ac6aab9e" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GeneralPartnerMember_15e26757-0d97-497e-b714-edc4c34edd36" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_GeneralPartnerMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PartnerTypeOfPartnersCapitalAccountNameDomain_cdceabaa-2cd3-489c-afe6-46445825a522" xlink:to="loc_us-gaap_GeneralPartnerMember_15e26757-0d97-497e-b714-edc4c34edd36" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LimitedPartnersCapitalAccountByClassAxis_5d1782de-4fc4-4847-ba23-d0620e8d793f" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LimitedPartnersCapitalAccountByClassAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_6de4ff7c-b07b-4acf-8531-a87e5eff2376" xlink:to="loc_us-gaap_LimitedPartnersCapitalAccountByClassAxis_5d1782de-4fc4-4847-ba23-d0620e8d793f" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_5d1782de-4fc4-4847-ba23-d0620e8d793f_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LimitedPartnersCapitalAccountClassDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountByClassAxis_5d1782de-4fc4-4847-ba23-d0620e8d793f" xlink:to="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_5d1782de-4fc4-4847-ba23-d0620e8d793f_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_62e0aafd-3a79-44ad-8d04-bd2fdfb3789a" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LimitedPartnersCapitalAccountClassDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountByClassAxis_5d1782de-4fc4-4847-ba23-d0620e8d793f" xlink:to="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_62e0aafd-3a79-44ad-8d04-bd2fdfb3789a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_wlkp_CommonUnitsMember_e2b27f0b-46cc-451d-a93e-248e8d589c15" xlink:href="wlkp-20211231.xsd#wlkp_CommonUnitsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_62e0aafd-3a79-44ad-8d04-bd2fdfb3789a" xlink:to="loc_wlkp_CommonUnitsMember_e2b27f0b-46cc-451d-a93e-248e8d589c15" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CounterpartyNameAxis_b17fcce8-5898-439a-9b2b-0c230d658e96" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_CounterpartyNameAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_6de4ff7c-b07b-4acf-8531-a87e5eff2376" xlink:to="loc_srt_CounterpartyNameAxis_b17fcce8-5898-439a-9b2b-0c230d658e96" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RepurchaseAgreementCounterpartyNameDomain_b17fcce8-5898-439a-9b2b-0c230d658e96_default" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RepurchaseAgreementCounterpartyNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_CounterpartyNameAxis_b17fcce8-5898-439a-9b2b-0c230d658e96" xlink:to="loc_srt_RepurchaseAgreementCounterpartyNameDomain_b17fcce8-5898-439a-9b2b-0c230d658e96_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RepurchaseAgreementCounterpartyNameDomain_fb5faa51-5040-4888-8472-018afc3cafa1" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RepurchaseAgreementCounterpartyNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_CounterpartyNameAxis_b17fcce8-5898-439a-9b2b-0c230d658e96" xlink:to="loc_srt_RepurchaseAgreementCounterpartyNameDomain_fb5faa51-5040-4888-8472-018afc3cafa1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_wlkp_UnidentifiedThirdPartiesMember_fec8d963-151e-45c5-9cb2-9656a7517eb0" xlink:href="wlkp-20211231.xsd#wlkp_UnidentifiedThirdPartiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RepurchaseAgreementCounterpartyNameDomain_fb5faa51-5040-4888-8472-018afc3cafa1" xlink:to="loc_wlkp_UnidentifiedThirdPartiesMember_fec8d963-151e-45c5-9cb2-9656a7517eb0" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember_09798651-a87d-474d-a62a-58d8c2cda953" xlink:href="wlkp-20211231.xsd#wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RepurchaseAgreementCounterpartyNameDomain_fb5faa51-5040-4888-8472-018afc3cafa1" xlink:to="loc_wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember_09798651-a87d-474d-a62a-58d8c2cda953" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.westlake.com/role/ConsolidatedBalanceSheetsParenthetical" xlink:type="simple" xlink:href="wlkp-20211231.xsd#ConsolidatedBalanceSheetsParenthetical"/>
  <link:definitionLink xlink:role="http://www.westlake.com/role/ConsolidatedBalanceSheetsParenthetical" xlink:type="extended" id="icd0b0d03ce2f40fe94e4e04d7c71cc58_ConsolidatedBalanceSheetsParenthetical">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems_37c4d744-b6dd-4725-b4e6-4d4e975d2803" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StatementLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LimitedPartnersCapitalAccountUnitsOutstanding_8162fd51-7812-49df-8737-abc362a64bd5" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LimitedPartnersCapitalAccountUnitsOutstanding"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_37c4d744-b6dd-4725-b4e6-4d4e975d2803" xlink:to="loc_us-gaap_LimitedPartnersCapitalAccountUnitsOutstanding_8162fd51-7812-49df-8737-abc362a64bd5" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LimitedPartnersCapitalAccountUnitsIssued_035d1249-fe14-4dc6-9121-add8078ce19d" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LimitedPartnersCapitalAccountUnitsIssued"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_37c4d744-b6dd-4725-b4e6-4d4e975d2803" xlink:to="loc_us-gaap_LimitedPartnersCapitalAccountUnitsIssued_035d1249-fe14-4dc6-9121-add8078ce19d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementTable_01b3811a-d6a5-4ab2-a183-fb6c0b49fb94" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StatementTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_37c4d744-b6dd-4725-b4e6-4d4e975d2803" xlink:to="loc_us-gaap_StatementTable_01b3811a-d6a5-4ab2-a183-fb6c0b49fb94" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LimitedPartnersCapitalAccountByClassAxis_9f631147-f050-4fef-8ad2-e7e2f215f767" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LimitedPartnersCapitalAccountByClassAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_01b3811a-d6a5-4ab2-a183-fb6c0b49fb94" xlink:to="loc_us-gaap_LimitedPartnersCapitalAccountByClassAxis_9f631147-f050-4fef-8ad2-e7e2f215f767" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_9f631147-f050-4fef-8ad2-e7e2f215f767_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LimitedPartnersCapitalAccountClassDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountByClassAxis_9f631147-f050-4fef-8ad2-e7e2f215f767" xlink:to="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_9f631147-f050-4fef-8ad2-e7e2f215f767_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_5e488d0e-4aad-4aee-9e18-ad436726032e" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LimitedPartnersCapitalAccountClassDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountByClassAxis_9f631147-f050-4fef-8ad2-e7e2f215f767" xlink:to="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_5e488d0e-4aad-4aee-9e18-ad436726032e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_wlkp_CommonUnitsMember_6416d295-003a-4d98-8d5b-fcb7dc2721d8" xlink:href="wlkp-20211231.xsd#wlkp_CommonUnitsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_5e488d0e-4aad-4aee-9e18-ad436726032e" xlink:to="loc_wlkp_CommonUnitsMember_6416d295-003a-4d98-8d5b-fcb7dc2721d8" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_wlkp_SubordinatedUnitsMember_d3dc7d9e-3c70-473e-af63-775343346330" xlink:href="wlkp-20211231.xsd#wlkp_SubordinatedUnitsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_5e488d0e-4aad-4aee-9e18-ad436726032e" xlink:to="loc_wlkp_SubordinatedUnitsMember_d3dc7d9e-3c70-473e-af63-775343346330" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CounterpartyNameAxis_8ce57b50-6b7f-4903-a611-e6717fa08f19" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_CounterpartyNameAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_01b3811a-d6a5-4ab2-a183-fb6c0b49fb94" xlink:to="loc_srt_CounterpartyNameAxis_8ce57b50-6b7f-4903-a611-e6717fa08f19" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RepurchaseAgreementCounterpartyNameDomain_8ce57b50-6b7f-4903-a611-e6717fa08f19_default" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RepurchaseAgreementCounterpartyNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_CounterpartyNameAxis_8ce57b50-6b7f-4903-a611-e6717fa08f19" xlink:to="loc_srt_RepurchaseAgreementCounterpartyNameDomain_8ce57b50-6b7f-4903-a611-e6717fa08f19_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RepurchaseAgreementCounterpartyNameDomain_b651c3c3-4663-4afe-a1c5-24430442f7b0" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RepurchaseAgreementCounterpartyNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_CounterpartyNameAxis_8ce57b50-6b7f-4903-a611-e6717fa08f19" xlink:to="loc_srt_RepurchaseAgreementCounterpartyNameDomain_b651c3c3-4663-4afe-a1c5-24430442f7b0" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember_02643b83-7bd1-4034-bbf7-7f5c89a83b87" xlink:href="wlkp-20211231.xsd#wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RepurchaseAgreementCounterpartyNameDomain_b651c3c3-4663-4afe-a1c5-24430442f7b0" xlink:to="loc_wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember_02643b83-7bd1-4034-bbf7-7f5c89a83b87" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_wlkp_UnidentifiedThirdPartiesMember_13e446e0-d0fb-44b0-8114-15e677f637ee" xlink:href="wlkp-20211231.xsd#wlkp_UnidentifiedThirdPartiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RepurchaseAgreementCounterpartyNameDomain_b651c3c3-4663-4afe-a1c5-24430442f7b0" xlink:to="loc_wlkp_UnidentifiedThirdPartiesMember_13e446e0-d0fb-44b0-8114-15e677f637ee" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.westlake.com/role/ConsolidatedStatementsofOperations" xlink:type="simple" xlink:href="wlkp-20211231.xsd#ConsolidatedStatementsofOperations"/>
  <link:definitionLink xlink:role="http://www.westlake.com/role/ConsolidatedStatementsofOperations" xlink:type="extended" id="i92f4042cc47d440e95ed3d23ec315fec_ConsolidatedStatementsofOperations">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems_ffa25987-009c-4663-8e28-f148117708b1" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StatementLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueFromRelatedParties_c768d05a-818d-45da-912e-86f66cc0be35" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RevenueFromRelatedParties"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_ffa25987-009c-4663-8e28-f148117708b1" xlink:to="loc_us-gaap_RevenueFromRelatedParties_c768d05a-818d-45da-912e-86f66cc0be35" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_da8f7a50-c2b4-4e70-b437-3756b0f5f87c" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_ffa25987-009c-4663-8e28-f148117708b1" xlink:to="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_da8f7a50-c2b4-4e70-b437-3756b0f5f87c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Revenues_c1b13b7f-10b9-44dc-9a36-68e221e16051" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_Revenues"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_ffa25987-009c-4663-8e28-f148117708b1" xlink:to="loc_us-gaap_Revenues_c1b13b7f-10b9-44dc-9a36-68e221e16051" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CostOfGoodsAndServicesSold_a56920ca-7a33-4f0d-a83f-5061e257b473" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CostOfGoodsAndServicesSold"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_ffa25987-009c-4663-8e28-f148117708b1" xlink:to="loc_us-gaap_CostOfGoodsAndServicesSold_a56920ca-7a33-4f0d-a83f-5061e257b473" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GrossProfit_680b4b7b-8a0a-45c1-9a92-1ecbea2570de" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_GrossProfit"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_ffa25987-009c-4663-8e28-f148117708b1" xlink:to="loc_us-gaap_GrossProfit_680b4b7b-8a0a-45c1-9a92-1ecbea2570de" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SellingGeneralAndAdministrativeExpense_e7bae74f-86c7-4075-a613-1dcbb1c011cb" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SellingGeneralAndAdministrativeExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_ffa25987-009c-4663-8e28-f148117708b1" xlink:to="loc_us-gaap_SellingGeneralAndAdministrativeExpense_e7bae74f-86c7-4075-a613-1dcbb1c011cb" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingIncomeLoss_60f7ba7a-dc17-408e-9f23-ae376a2924b3" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OperatingIncomeLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_ffa25987-009c-4663-8e28-f148117708b1" xlink:to="loc_us-gaap_OperatingIncomeLoss_60f7ba7a-dc17-408e-9f23-ae376a2924b3" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NonoperatingIncomeExpenseAbstract_230586c6-e01d-41ad-9662-1e9e2a5ea8cf" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_NonoperatingIncomeExpenseAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_ffa25987-009c-4663-8e28-f148117708b1" xlink:to="loc_us-gaap_NonoperatingIncomeExpenseAbstract_230586c6-e01d-41ad-9662-1e9e2a5ea8cf" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestExpenseRelatedParty_1fadf7ff-c6ea-412c-8545-5b7b6d27e6ce" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_InterestExpenseRelatedParty"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NonoperatingIncomeExpenseAbstract_230586c6-e01d-41ad-9662-1e9e2a5ea8cf" xlink:to="loc_us-gaap_InterestExpenseRelatedParty_1fadf7ff-c6ea-412c-8545-5b7b6d27e6ce" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NonoperatingIncomeExpense_d312ba16-28e7-4a6c-b344-6a8323c2b091" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_NonoperatingIncomeExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NonoperatingIncomeExpenseAbstract_230586c6-e01d-41ad-9662-1e9e2a5ea8cf" xlink:to="loc_us-gaap_NonoperatingIncomeExpense_d312ba16-28e7-4a6c-b344-6a8323c2b091" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest_a721b26b-009b-4836-a127-50ae01d2bdc6" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_ffa25987-009c-4663-8e28-f148117708b1" xlink:to="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest_a721b26b-009b-4836-a127-50ae01d2bdc6" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxExpenseBenefit_d29723d4-e0a8-45a6-96f1-7337d3c842a7" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncomeTaxExpenseBenefit"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_ffa25987-009c-4663-8e28-f148117708b1" xlink:to="loc_us-gaap_IncomeTaxExpenseBenefit_d29723d4-e0a8-45a6-96f1-7337d3c842a7" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProfitLoss_e6f7576d-abec-4a4c-b594-284df18c8e03" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ProfitLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_ffa25987-009c-4663-8e28-f148117708b1" xlink:to="loc_us-gaap_ProfitLoss_e6f7576d-abec-4a4c-b594-284df18c8e03" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLossAttributableToNoncontrollingInterest_090a1658-218a-4a33-ae45-d30d78a19d85" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_NetIncomeLossAttributableToNoncontrollingInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_ffa25987-009c-4663-8e28-f148117708b1" xlink:to="loc_us-gaap_NetIncomeLossAttributableToNoncontrollingInterest_090a1658-218a-4a33-ae45-d30d78a19d85" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLoss_cfdfe6b9-1fed-4115-a9fa-6176b8deda19" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_NetIncomeLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_ffa25987-009c-4663-8e28-f148117708b1" xlink:to="loc_us-gaap_NetIncomeLoss_cfdfe6b9-1fed-4115-a9fa-6176b8deda19" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLossPerOutstandingLimitedPartnershipUnitBasicNetOfTax_284af245-7ddc-40be-a521-66ae69846623" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_NetIncomeLossPerOutstandingLimitedPartnershipUnitBasicNetOfTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_ffa25987-009c-4663-8e28-f148117708b1" xlink:to="loc_us-gaap_NetIncomeLossPerOutstandingLimitedPartnershipUnitBasicNetOfTax_284af245-7ddc-40be-a521-66ae69846623" xlink:type="arc" order="13"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EarningsPerShareBasicAndDilutedAbstract_4b2c418a-cfd8-4bba-9e20-c662698d549c" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EarningsPerShareBasicAndDilutedAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_ffa25987-009c-4663-8e28-f148117708b1" xlink:to="loc_us-gaap_EarningsPerShareBasicAndDilutedAbstract_4b2c418a-cfd8-4bba-9e20-c662698d549c" xlink:type="arc" order="14"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EarningsPerShareBasicAndDilutedOtherDisclosuresAbstract_a78a9ed0-15a7-41f7-bfcb-4d445c44ef26" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EarningsPerShareBasicAndDilutedOtherDisclosuresAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_ffa25987-009c-4663-8e28-f148117708b1" xlink:to="loc_us-gaap_EarningsPerShareBasicAndDilutedOtherDisclosuresAbstract_a78a9ed0-15a7-41f7-bfcb-4d445c44ef26" xlink:type="arc" order="15"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_WeightedAverageNumberOfShareOutstandingBasicAndDiluted_32fe4283-8d7e-4e52-997a-994272f3560d" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_WeightedAverageNumberOfShareOutstandingBasicAndDiluted"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EarningsPerShareBasicAndDilutedOtherDisclosuresAbstract_a78a9ed0-15a7-41f7-bfcb-4d445c44ef26" xlink:to="loc_us-gaap_WeightedAverageNumberOfShareOutstandingBasicAndDiluted_32fe4283-8d7e-4e52-997a-994272f3560d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementTable_391d6437-8413-4267-9b4e-debee5d1e126" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StatementTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_ffa25987-009c-4663-8e28-f148117708b1" xlink:to="loc_us-gaap_StatementTable_391d6437-8413-4267-9b4e-debee5d1e126" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CounterpartyNameAxis_df54ab03-ea73-419d-af1b-da71b9f2fb44" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_CounterpartyNameAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_391d6437-8413-4267-9b4e-debee5d1e126" xlink:to="loc_srt_CounterpartyNameAxis_df54ab03-ea73-419d-af1b-da71b9f2fb44" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RepurchaseAgreementCounterpartyNameDomain_df54ab03-ea73-419d-af1b-da71b9f2fb44_default" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RepurchaseAgreementCounterpartyNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_CounterpartyNameAxis_df54ab03-ea73-419d-af1b-da71b9f2fb44" xlink:to="loc_srt_RepurchaseAgreementCounterpartyNameDomain_df54ab03-ea73-419d-af1b-da71b9f2fb44_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RepurchaseAgreementCounterpartyNameDomain_8826d0a0-16c8-4e4d-9aca-b3de8c2469fe" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RepurchaseAgreementCounterpartyNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_CounterpartyNameAxis_df54ab03-ea73-419d-af1b-da71b9f2fb44" xlink:to="loc_srt_RepurchaseAgreementCounterpartyNameDomain_8826d0a0-16c8-4e4d-9aca-b3de8c2469fe" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_wlkp_UnidentifiedThirdPartiesMember_60e56c16-fbe6-4586-98be-2a6a8b0b19aa" xlink:href="wlkp-20211231.xsd#wlkp_UnidentifiedThirdPartiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RepurchaseAgreementCounterpartyNameDomain_8826d0a0-16c8-4e4d-9aca-b3de8c2469fe" xlink:to="loc_wlkp_UnidentifiedThirdPartiesMember_60e56c16-fbe6-4586-98be-2a6a8b0b19aa" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember_2cdb5462-cb69-4172-a512-98845c67743d" xlink:href="wlkp-20211231.xsd#wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RepurchaseAgreementCounterpartyNameDomain_8826d0a0-16c8-4e4d-9aca-b3de8c2469fe" xlink:to="loc_wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember_2cdb5462-cb69-4172-a512-98845c67743d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LimitedPartnersCapitalAccountByClassAxis_e9cead82-2173-4b20-aec7-2053397089e1" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LimitedPartnersCapitalAccountByClassAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_391d6437-8413-4267-9b4e-debee5d1e126" xlink:to="loc_us-gaap_LimitedPartnersCapitalAccountByClassAxis_e9cead82-2173-4b20-aec7-2053397089e1" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_e9cead82-2173-4b20-aec7-2053397089e1_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LimitedPartnersCapitalAccountClassDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountByClassAxis_e9cead82-2173-4b20-aec7-2053397089e1" xlink:to="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_e9cead82-2173-4b20-aec7-2053397089e1_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_4937093f-d13e-42b3-9696-e37c6d66e21b" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LimitedPartnersCapitalAccountClassDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountByClassAxis_e9cead82-2173-4b20-aec7-2053397089e1" xlink:to="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_4937093f-d13e-42b3-9696-e37c6d66e21b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_wlkp_CommonUnitsMember_29742f92-5dff-4e33-b477-f0f500b4985e" xlink:href="wlkp-20211231.xsd#wlkp_CommonUnitsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_4937093f-d13e-42b3-9696-e37c6d66e21b" xlink:to="loc_wlkp_CommonUnitsMember_29742f92-5dff-4e33-b477-f0f500b4985e" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.westlake.com/role/ConsolidatedStatementsofChangesinEquity" xlink:type="simple" xlink:href="wlkp-20211231.xsd#ConsolidatedStatementsofChangesinEquity"/>
  <link:definitionLink xlink:role="http://www.westlake.com/role/ConsolidatedStatementsofChangesinEquity" xlink:type="extended" id="i8cf61da200404ef19deb6a7363931c6e_ConsolidatedStatementsofChangesinEquity">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems_fc5f249f-a719-4f99-bf8e-e58dff7b2c54" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StatementLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_5e9de248-3ea1-4f18-b26f-95c80a622000" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncreaseDecreaseInStockholdersEquityRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_fc5f249f-a719-4f99-bf8e-e58dff7b2c54" xlink:to="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_5e9de248-3ea1-4f18-b26f-95c80a622000" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PartnersCapitalIncludingPortionAttributableToNoncontrollingInterest_130b500e-ee5b-4509-92b3-aee1880b8542" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PartnersCapitalIncludingPortionAttributableToNoncontrollingInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_5e9de248-3ea1-4f18-b26f-95c80a622000" xlink:to="loc_us-gaap_PartnersCapitalIncludingPortionAttributableToNoncontrollingInterest_130b500e-ee5b-4509-92b3-aee1880b8542" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProfitLoss_e6ebeae3-fe76-4fef-9d07-31325c638623" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ProfitLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_5e9de248-3ea1-4f18-b26f-95c80a622000" xlink:to="loc_us-gaap_ProfitLoss_e6ebeae3-fe76-4fef-9d07-31325c638623" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossDerivativesQualifyingAsHedgesNetOfTax_16db9b5e-91c9-4df4-a654-ab389a831ff4" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossDerivativesQualifyingAsHedgesNetOfTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_5e9de248-3ea1-4f18-b26f-95c80a622000" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossDerivativesQualifyingAsHedgesNetOfTax_16db9b5e-91c9-4df4-a654-ab389a831ff4" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodValueOther_bb591b8b-5a54-47e6-a1c1-652372cce6ea" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StockIssuedDuringPeriodValueOther"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_5e9de248-3ea1-4f18-b26f-95c80a622000" xlink:to="loc_us-gaap_StockIssuedDuringPeriodValueOther_bb591b8b-5a54-47e6-a1c1-652372cce6ea" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProceedsFromIssuanceOrSaleOfEquity_dafe6cf9-ef04-4746-a5ee-13bce4124763" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ProceedsFromIssuanceOrSaleOfEquity"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_5e9de248-3ea1-4f18-b26f-95c80a622000" xlink:to="loc_us-gaap_ProceedsFromIssuanceOrSaleOfEquity_dafe6cf9-ef04-4746-a5ee-13bce4124763" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_wlkp_ConversionofUnitsAmount_cec4c2e8-94b1-44d8-8caa-56d9ee522f6d" xlink:href="wlkp-20211231.xsd#wlkp_ConversionofUnitsAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_5e9de248-3ea1-4f18-b26f-95c80a622000" xlink:to="loc_wlkp_ConversionofUnitsAmount_cec4c2e8-94b1-44d8-8caa-56d9ee522f6d" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LimitedPartnersCapitalAccountDistributionAmount_75f712ca-be6d-409e-9a07-2e2dcb63b524" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LimitedPartnersCapitalAccountDistributionAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_5e9de248-3ea1-4f18-b26f-95c80a622000" xlink:to="loc_us-gaap_LimitedPartnersCapitalAccountDistributionAmount_75f712ca-be6d-409e-9a07-2e2dcb63b524" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MinorityInterestDecreaseFromDistributionsToNoncontrollingInterestHolders_749bf5f7-f616-4a11-b525-dab499b187cf" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_MinorityInterestDecreaseFromDistributionsToNoncontrollingInterestHolders"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_5e9de248-3ea1-4f18-b26f-95c80a622000" xlink:to="loc_us-gaap_MinorityInterestDecreaseFromDistributionsToNoncontrollingInterestHolders_749bf5f7-f616-4a11-b525-dab499b187cf" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PartnersCapitalIncludingPortionAttributableToNoncontrollingInterest_b54cf897-5dea-4390-9a5a-360d92348cd7" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PartnersCapitalIncludingPortionAttributableToNoncontrollingInterest"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementTable_2b7520b9-9b8b-4476-b883-6eae30f5ab65" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StatementTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_fc5f249f-a719-4f99-bf8e-e58dff7b2c54" xlink:to="loc_us-gaap_StatementTable_2b7520b9-9b8b-4476-b883-6eae30f5ab65" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LimitedPartnersCapitalAccountByClassAxis_cb46c48c-c771-4ef6-9412-5b791924038f" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LimitedPartnersCapitalAccountByClassAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_2b7520b9-9b8b-4476-b883-6eae30f5ab65" xlink:to="loc_us-gaap_LimitedPartnersCapitalAccountByClassAxis_cb46c48c-c771-4ef6-9412-5b791924038f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_cb46c48c-c771-4ef6-9412-5b791924038f_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LimitedPartnersCapitalAccountClassDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountByClassAxis_cb46c48c-c771-4ef6-9412-5b791924038f" xlink:to="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_cb46c48c-c771-4ef6-9412-5b791924038f_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_0b7bbfcc-88b5-4d47-8f1c-6bb33c7fd63c" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LimitedPartnersCapitalAccountClassDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountByClassAxis_cb46c48c-c771-4ef6-9412-5b791924038f" xlink:to="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_0b7bbfcc-88b5-4d47-8f1c-6bb33c7fd63c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_wlkp_CommonUnitsMember_b2c9695c-00ab-4906-beae-356337b78d77" xlink:href="wlkp-20211231.xsd#wlkp_CommonUnitsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_0b7bbfcc-88b5-4d47-8f1c-6bb33c7fd63c" xlink:to="loc_wlkp_CommonUnitsMember_b2c9695c-00ab-4906-beae-356337b78d77" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_wlkp_SubordinatedUnitsMember_9dfdda17-6876-470f-9a81-da41fa740e06" xlink:href="wlkp-20211231.xsd#wlkp_SubordinatedUnitsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_0b7bbfcc-88b5-4d47-8f1c-6bb33c7fd63c" xlink:to="loc_wlkp_SubordinatedUnitsMember_9dfdda17-6876-470f-9a81-da41fa740e06" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CounterpartyNameAxis_d9eb55b3-abcf-49e9-9f8f-d421a270f9a4" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_CounterpartyNameAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_2b7520b9-9b8b-4476-b883-6eae30f5ab65" xlink:to="loc_srt_CounterpartyNameAxis_d9eb55b3-abcf-49e9-9f8f-d421a270f9a4" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RepurchaseAgreementCounterpartyNameDomain_d9eb55b3-abcf-49e9-9f8f-d421a270f9a4_default" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RepurchaseAgreementCounterpartyNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_CounterpartyNameAxis_d9eb55b3-abcf-49e9-9f8f-d421a270f9a4" xlink:to="loc_srt_RepurchaseAgreementCounterpartyNameDomain_d9eb55b3-abcf-49e9-9f8f-d421a270f9a4_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RepurchaseAgreementCounterpartyNameDomain_db14c0fa-4447-4365-8d57-56ceab81fd8e" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RepurchaseAgreementCounterpartyNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_CounterpartyNameAxis_d9eb55b3-abcf-49e9-9f8f-d421a270f9a4" xlink:to="loc_srt_RepurchaseAgreementCounterpartyNameDomain_db14c0fa-4447-4365-8d57-56ceab81fd8e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_wlkp_UnidentifiedThirdPartiesMember_2fe87ad7-f76b-4e3b-8ce9-5841fb72dd32" xlink:href="wlkp-20211231.xsd#wlkp_UnidentifiedThirdPartiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RepurchaseAgreementCounterpartyNameDomain_db14c0fa-4447-4365-8d57-56ceab81fd8e" xlink:to="loc_wlkp_UnidentifiedThirdPartiesMember_2fe87ad7-f76b-4e3b-8ce9-5841fb72dd32" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember_fcd23557-d39c-4b34-8ba1-ce6e767ce6a6" xlink:href="wlkp-20211231.xsd#wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RepurchaseAgreementCounterpartyNameDomain_db14c0fa-4447-4365-8d57-56ceab81fd8e" xlink:to="loc_wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember_fcd23557-d39c-4b34-8ba1-ce6e767ce6a6" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PartnerTypeOfPartnersCapitalAccountAxis_0917a9bb-120b-4c49-9098-0f33f1bef3b6" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PartnerTypeOfPartnersCapitalAccountAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_2b7520b9-9b8b-4476-b883-6eae30f5ab65" xlink:to="loc_us-gaap_PartnerTypeOfPartnersCapitalAccountAxis_0917a9bb-120b-4c49-9098-0f33f1bef3b6" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PartnerTypeOfPartnersCapitalAccountNameDomain_0917a9bb-120b-4c49-9098-0f33f1bef3b6_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PartnerTypeOfPartnersCapitalAccountNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_PartnerTypeOfPartnersCapitalAccountAxis_0917a9bb-120b-4c49-9098-0f33f1bef3b6" xlink:to="loc_us-gaap_PartnerTypeOfPartnersCapitalAccountNameDomain_0917a9bb-120b-4c49-9098-0f33f1bef3b6_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PartnerTypeOfPartnersCapitalAccountNameDomain_434d0baf-cead-4cde-b475-8c71e0dba286" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PartnerTypeOfPartnersCapitalAccountNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_PartnerTypeOfPartnersCapitalAccountAxis_0917a9bb-120b-4c49-9098-0f33f1bef3b6" xlink:to="loc_us-gaap_PartnerTypeOfPartnersCapitalAccountNameDomain_434d0baf-cead-4cde-b475-8c71e0dba286" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LimitedPartnerMember_427ac903-3dbe-434e-a1ef-ab3745ba3a86" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LimitedPartnerMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PartnerTypeOfPartnersCapitalAccountNameDomain_434d0baf-cead-4cde-b475-8c71e0dba286" xlink:to="loc_us-gaap_LimitedPartnerMember_427ac903-3dbe-434e-a1ef-ab3745ba3a86" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GeneralPartnerMember_d3d55cd1-f0d7-441e-be68-8bee653630e5" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_GeneralPartnerMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PartnerTypeOfPartnersCapitalAccountNameDomain_434d0baf-cead-4cde-b475-8c71e0dba286" xlink:to="loc_us-gaap_GeneralPartnerMember_d3d55cd1-f0d7-441e-be68-8bee653630e5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementEquityComponentsAxis_fe7369da-3a00-49b2-a0b2-77be7e36bf36" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StatementEquityComponentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_2b7520b9-9b8b-4476-b883-6eae30f5ab65" xlink:to="loc_us-gaap_StatementEquityComponentsAxis_fe7369da-3a00-49b2-a0b2-77be7e36bf36" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_fe7369da-3a00-49b2-a0b2-77be7e36bf36_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_fe7369da-3a00-49b2-a0b2-77be7e36bf36" xlink:to="loc_us-gaap_EquityComponentDomain_fe7369da-3a00-49b2-a0b2-77be7e36bf36_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_2960b90f-e30e-4e9d-9ea1-277803868604" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_fe7369da-3a00-49b2-a0b2-77be7e36bf36" xlink:to="loc_us-gaap_EquityComponentDomain_2960b90f-e30e-4e9d-9ea1-277803868604" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NoncontrollingInterestMember_95f37c5d-9381-4f3c-9e70-b71c2d9603d0" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_NoncontrollingInterestMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_2960b90f-e30e-4e9d-9ea1-277803868604" xlink:to="loc_us-gaap_NoncontrollingInterestMember_95f37c5d-9381-4f3c-9e70-b71c2d9603d0" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.westlake.com/role/DescriptionofBusinessandSignificantAccountingPoliciesNarrativeDetails" xlink:type="simple" xlink:href="wlkp-20211231.xsd#DescriptionofBusinessandSignificantAccountingPoliciesNarrativeDetails"/>
  <link:definitionLink xlink:role="http://www.westlake.com/role/DescriptionofBusinessandSignificantAccountingPoliciesNarrativeDetails" xlink:type="extended" id="ia8454ff40270491187f5a5b97ed5c5c3_DescriptionofBusinessandSignificantAccountingPoliciesNarrativeDetails">
    <link:loc xlink:type="locator" xlink:label="loc_wlkp_OrganizationConsolidationAndPresentationOfFinancialStatementsLineItems_f2386821-42ec-4972-8c8f-b02f49a1f7b0" xlink:href="wlkp-20211231.xsd#wlkp_OrganizationConsolidationAndPresentationOfFinancialStatementsLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PartnersCapitalAccountUnitsSoldInPublicOffering_377171c8-b160-44f3-8f5a-c5926bfc2ed3" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PartnersCapitalAccountUnitsSoldInPublicOffering"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_wlkp_OrganizationConsolidationAndPresentationOfFinancialStatementsLineItems_f2386821-42ec-4972-8c8f-b02f49a1f7b0" xlink:to="loc_us-gaap_PartnersCapitalAccountUnitsSoldInPublicOffering_377171c8-b160-44f3-8f5a-c5926bfc2ed3" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LimitedLiabilityCompanyLLCOrLimitedPartnershipLPMembersOrLimitedPartnersOwnershipInterest_575361bc-f537-4532-8fa7-b04cc7017e57" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LimitedLiabilityCompanyLLCOrLimitedPartnershipLPMembersOrLimitedPartnersOwnershipInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_wlkp_OrganizationConsolidationAndPresentationOfFinancialStatementsLineItems_f2386821-42ec-4972-8c8f-b02f49a1f7b0" xlink:to="loc_us-gaap_LimitedLiabilityCompanyLLCOrLimitedPartnershipLPMembersOrLimitedPartnersOwnershipInterest_575361bc-f537-4532-8fa7-b04cc7017e57" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_wlkp_NumberofProductionFacilities_dc686ad8-c945-44e9-b9c2-e83eba8a6aea" xlink:href="wlkp-20211231.xsd#wlkp_NumberofProductionFacilities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_wlkp_OrganizationConsolidationAndPresentationOfFinancialStatementsLineItems_f2386821-42ec-4972-8c8f-b02f49a1f7b0" xlink:to="loc_wlkp_NumberofProductionFacilities_dc686ad8-c945-44e9-b9c2-e83eba8a6aea" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_wlkp_LimitedLiabilityCompanyLLCorLimitedPartnershipLPMembersorLimitedPartnersAdditionalOwnershipInterest_b1911ee2-5498-464b-923f-97e22070f2e5" xlink:href="wlkp-20211231.xsd#wlkp_LimitedLiabilityCompanyLLCorLimitedPartnershipLPMembersorLimitedPartnersAdditionalOwnershipInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_wlkp_OrganizationConsolidationAndPresentationOfFinancialStatementsLineItems_f2386821-42ec-4972-8c8f-b02f49a1f7b0" xlink:to="loc_wlkp_LimitedLiabilityCompanyLLCorLimitedPartnershipLPMembersorLimitedPartnersAdditionalOwnershipInterest_b1911ee2-5498-464b-923f-97e22070f2e5" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentsToAcquireLimitedPartnershipInterests_18f73c0d-767a-4abe-bf36-3fa3ac12cbbc" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PaymentsToAcquireLimitedPartnershipInterests"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_wlkp_OrganizationConsolidationAndPresentationOfFinancialStatementsLineItems_f2386821-42ec-4972-8c8f-b02f49a1f7b0" xlink:to="loc_us-gaap_PaymentsToAcquireLimitedPartnershipInterests_18f73c0d-767a-4abe-bf36-3fa3ac12cbbc" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_wlkp_ThresholdPeriodPastDueAccountsReceivableReviewed_b1f55ef0-3ffd-4fc9-a12c-0c21a7759dac" xlink:href="wlkp-20211231.xsd#wlkp_ThresholdPeriodPastDueAccountsReceivableReviewed"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_wlkp_OrganizationConsolidationAndPresentationOfFinancialStatementsLineItems_f2386821-42ec-4972-8c8f-b02f49a1f7b0" xlink:to="loc_wlkp_ThresholdPeriodPastDueAccountsReceivableReviewed_b1f55ef0-3ffd-4fc9-a12c-0c21a7759dac" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestCostsCapitalized_d79315b2-d8ad-4af2-bea6-1644a5e85812" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_InterestCostsCapitalized"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_wlkp_OrganizationConsolidationAndPresentationOfFinancialStatementsLineItems_f2386821-42ec-4972-8c8f-b02f49a1f7b0" xlink:to="loc_us-gaap_InterestCostsCapitalized_d79315b2-d8ad-4af2-bea6-1644a5e85812" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Goodwill_296599be-57ba-4ff0-b938-f14072a2feb7" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_Goodwill"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_wlkp_OrganizationConsolidationAndPresentationOfFinancialStatementsLineItems_f2386821-42ec-4972-8c8f-b02f49a1f7b0" xlink:to="loc_us-gaap_Goodwill_296599be-57ba-4ff0-b938-f14072a2feb7" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_wlkp_PlantAndEquipmentPlannedMajorMaintenanceActivitiesAmortizationPeriodMaximum_7e6e8b4b-78fc-4443-9517-7876d753ac36" xlink:href="wlkp-20211231.xsd#wlkp_PlantAndEquipmentPlannedMajorMaintenanceActivitiesAmortizationPeriodMaximum"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_wlkp_OrganizationConsolidationAndPresentationOfFinancialStatementsLineItems_f2386821-42ec-4972-8c8f-b02f49a1f7b0" xlink:to="loc_wlkp_PlantAndEquipmentPlannedMajorMaintenanceActivitiesAmortizationPeriodMaximum_7e6e8b4b-78fc-4443-9517-7876d753ac36" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_wlkp_PlantAndEquipmentPlannedMajorMaintenanceActivitiesAmortizationPeriodMinimum_3ee7d443-f45d-4db6-949a-1f9284e7a6cf" xlink:href="wlkp-20211231.xsd#wlkp_PlantAndEquipmentPlannedMajorMaintenanceActivitiesAmortizationPeriodMinimum"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_wlkp_OrganizationConsolidationAndPresentationOfFinancialStatementsLineItems_f2386821-42ec-4972-8c8f-b02f49a1f7b0" xlink:to="loc_wlkp_PlantAndEquipmentPlannedMajorMaintenanceActivitiesAmortizationPeriodMinimum_3ee7d443-f45d-4db6-949a-1f9284e7a6cf" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_wlkp_PartnersCapitalAccountUnitsSoldinPublicOfferingPriceperUnit_dae824a7-ffaa-4fb2-bf9b-5fbb7045605c" xlink:href="wlkp-20211231.xsd#wlkp_PartnersCapitalAccountUnitsSoldinPublicOfferingPriceperUnit"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_wlkp_OrganizationConsolidationAndPresentationOfFinancialStatementsLineItems_f2386821-42ec-4972-8c8f-b02f49a1f7b0" xlink:to="loc_wlkp_PartnersCapitalAccountUnitsSoldinPublicOfferingPriceperUnit_dae824a7-ffaa-4fb2-bf9b-5fbb7045605c" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProceedsFromIssuanceOrSaleOfEquity_8af05249-5342-4cb2-9700-9ce3ca96e8bc" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ProceedsFromIssuanceOrSaleOfEquity"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_wlkp_OrganizationConsolidationAndPresentationOfFinancialStatementsLineItems_f2386821-42ec-4972-8c8f-b02f49a1f7b0" xlink:to="loc_us-gaap_ProceedsFromIssuanceOrSaleOfEquity_8af05249-5342-4cb2-9700-9ce3ca96e8bc" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_wlkp_OrganizationConsolidationAndPresentationOfFinancialStatementsTable_63513d64-498a-4dab-8c3c-e87cbfedd637" xlink:href="wlkp-20211231.xsd#wlkp_OrganizationConsolidationAndPresentationOfFinancialStatementsTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_wlkp_OrganizationConsolidationAndPresentationOfFinancialStatementsLineItems_f2386821-42ec-4972-8c8f-b02f49a1f7b0" xlink:to="loc_wlkp_OrganizationConsolidationAndPresentationOfFinancialStatementsTable_63513d64-498a-4dab-8c3c-e87cbfedd637" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PartnerTypeOfPartnersCapitalAccountAxis_c22c0791-25d7-4be0-8ba5-325c8116b370" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PartnerTypeOfPartnersCapitalAccountAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_wlkp_OrganizationConsolidationAndPresentationOfFinancialStatementsTable_63513d64-498a-4dab-8c3c-e87cbfedd637" xlink:to="loc_us-gaap_PartnerTypeOfPartnersCapitalAccountAxis_c22c0791-25d7-4be0-8ba5-325c8116b370" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PartnerTypeOfPartnersCapitalAccountNameDomain_c22c0791-25d7-4be0-8ba5-325c8116b370_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PartnerTypeOfPartnersCapitalAccountNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_PartnerTypeOfPartnersCapitalAccountAxis_c22c0791-25d7-4be0-8ba5-325c8116b370" xlink:to="loc_us-gaap_PartnerTypeOfPartnersCapitalAccountNameDomain_c22c0791-25d7-4be0-8ba5-325c8116b370_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PartnerTypeOfPartnersCapitalAccountNameDomain_a0fc9b06-6405-4e03-80c6-f93b6897d1ce" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PartnerTypeOfPartnersCapitalAccountNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_PartnerTypeOfPartnersCapitalAccountAxis_c22c0791-25d7-4be0-8ba5-325c8116b370" xlink:to="loc_us-gaap_PartnerTypeOfPartnersCapitalAccountNameDomain_a0fc9b06-6405-4e03-80c6-f93b6897d1ce" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LimitedPartnerMember_af4de553-3f58-432a-9686-d4e932a84bb4" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LimitedPartnerMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PartnerTypeOfPartnersCapitalAccountNameDomain_a0fc9b06-6405-4e03-80c6-f93b6897d1ce" xlink:to="loc_us-gaap_LimitedPartnerMember_af4de553-3f58-432a-9686-d4e932a84bb4" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_LegalEntityAxis_a98eea44-43e2-47c0-82d0-85b77f939d86" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_LegalEntityAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_wlkp_OrganizationConsolidationAndPresentationOfFinancialStatementsTable_63513d64-498a-4dab-8c3c-e87cbfedd637" xlink:to="loc_dei_LegalEntityAxis_a98eea44-43e2-47c0-82d0-85b77f939d86" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityDomain_a98eea44-43e2-47c0-82d0-85b77f939d86_default" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_EntityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_dei_LegalEntityAxis_a98eea44-43e2-47c0-82d0-85b77f939d86" xlink:to="loc_dei_EntityDomain_a98eea44-43e2-47c0-82d0-85b77f939d86_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityDomain_c34d0ffd-54f1-47e0-8325-e48d7f908058" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_EntityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_dei_LegalEntityAxis_a98eea44-43e2-47c0-82d0-85b77f939d86" xlink:to="loc_dei_EntityDomain_c34d0ffd-54f1-47e0-8325-e48d7f908058" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember_62ad5e47-6e66-4d99-8d54-c4b85e55a559" xlink:href="wlkp-20211231.xsd#wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_c34d0ffd-54f1-47e0-8325-e48d7f908058" xlink:to="loc_wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember_62ad5e47-6e66-4d99-8d54-c4b85e55a559" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_wlkp_WestlakeChemicalOpCoLPMember_4f055b75-8851-4807-be57-fcb3f1b9ff95" xlink:href="wlkp-20211231.xsd#wlkp_WestlakeChemicalOpCoLPMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_c34d0ffd-54f1-47e0-8325-e48d7f908058" xlink:to="loc_wlkp_WestlakeChemicalOpCoLPMember_4f055b75-8851-4807-be57-fcb3f1b9ff95" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_13d7be0e-4382-44fa-beee-1181fd3849d3" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_wlkp_OrganizationConsolidationAndPresentationOfFinancialStatementsTable_63513d64-498a-4dab-8c3c-e87cbfedd637" xlink:to="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_13d7be0e-4382-44fa-beee-1181fd3849d3" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_13d7be0e-4382-44fa-beee-1181fd3849d3_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_13d7be0e-4382-44fa-beee-1181fd3849d3" xlink:to="loc_us-gaap_RelatedPartyDomain_13d7be0e-4382-44fa-beee-1181fd3849d3_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_a2d7e570-b268-4ab3-b8e8-71b654271eb7" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_13d7be0e-4382-44fa-beee-1181fd3849d3" xlink:to="loc_us-gaap_RelatedPartyDomain_a2d7e570-b268-4ab3-b8e8-71b654271eb7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LimitedLiabilityCompanyMember_bbd50527-a4c3-4305-a843-1c8fc4acb176" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LimitedLiabilityCompanyMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyDomain_a2d7e570-b268-4ab3-b8e8-71b654271eb7" xlink:to="loc_us-gaap_LimitedLiabilityCompanyMember_bbd50527-a4c3-4305-a843-1c8fc4acb176" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MajorityOwnedSubsidiaryUnconsolidatedMember_65d8a394-1c64-471b-96aa-7636a40cb3fa" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_MajorityOwnedSubsidiaryUnconsolidatedMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyDomain_a2d7e570-b268-4ab3-b8e8-71b654271eb7" xlink:to="loc_us-gaap_MajorityOwnedSubsidiaryUnconsolidatedMember_65d8a394-1c64-471b-96aa-7636a40cb3fa" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_AffiliatedEntityMember_e2121891-457d-4024-aa37-32e6f122f6b4" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_AffiliatedEntityMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyDomain_a2d7e570-b268-4ab3-b8e8-71b654271eb7" xlink:to="loc_srt_AffiliatedEntityMember_e2121891-457d-4024-aa37-32e6f122f6b4" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CounterpartyNameAxis_60bfde17-782b-49d7-b106-2617f1db034a" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_CounterpartyNameAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_wlkp_OrganizationConsolidationAndPresentationOfFinancialStatementsTable_63513d64-498a-4dab-8c3c-e87cbfedd637" xlink:to="loc_srt_CounterpartyNameAxis_60bfde17-782b-49d7-b106-2617f1db034a" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RepurchaseAgreementCounterpartyNameDomain_60bfde17-782b-49d7-b106-2617f1db034a_default" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RepurchaseAgreementCounterpartyNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_CounterpartyNameAxis_60bfde17-782b-49d7-b106-2617f1db034a" xlink:to="loc_srt_RepurchaseAgreementCounterpartyNameDomain_60bfde17-782b-49d7-b106-2617f1db034a_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RepurchaseAgreementCounterpartyNameDomain_10334a35-510f-4734-aa44-ac7bbc25ede3" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RepurchaseAgreementCounterpartyNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_CounterpartyNameAxis_60bfde17-782b-49d7-b106-2617f1db034a" xlink:to="loc_srt_RepurchaseAgreementCounterpartyNameDomain_10334a35-510f-4734-aa44-ac7bbc25ede3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember_e3245edc-58b1-4daa-870f-822a9d416cb4" xlink:href="wlkp-20211231.xsd#wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RepurchaseAgreementCounterpartyNameDomain_10334a35-510f-4734-aa44-ac7bbc25ede3" xlink:to="loc_wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember_e3245edc-58b1-4daa-870f-822a9d416cb4" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_wlkp_WestlakeChemicalOpCoLPMember_8e6ce69f-4c7a-4dc2-a064-b5abca4afe04" xlink:href="wlkp-20211231.xsd#wlkp_WestlakeChemicalOpCoLPMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RepurchaseAgreementCounterpartyNameDomain_10334a35-510f-4734-aa44-ac7bbc25ede3" xlink:to="loc_wlkp_WestlakeChemicalOpCoLPMember_8e6ce69f-4c7a-4dc2-a064-b5abca4afe04" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_wlkp_WestlakeChemicalOpCoGPLLCMember_a2ed2c39-5367-4166-af5d-8df07c563053" xlink:href="wlkp-20211231.xsd#wlkp_WestlakeChemicalOpCoGPLLCMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RepurchaseAgreementCounterpartyNameDomain_10334a35-510f-4734-aa44-ac7bbc25ede3" xlink:to="loc_wlkp_WestlakeChemicalOpCoGPLLCMember_a2ed2c39-5367-4166-af5d-8df07c563053" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_OwnershipAxis_da94f5fb-aa90-4e05-874f-5f6cd3e1cd30" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_OwnershipAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_wlkp_OrganizationConsolidationAndPresentationOfFinancialStatementsTable_63513d64-498a-4dab-8c3c-e87cbfedd637" xlink:to="loc_srt_OwnershipAxis_da94f5fb-aa90-4e05-874f-5f6cd3e1cd30" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_OwnershipDomain_da94f5fb-aa90-4e05-874f-5f6cd3e1cd30_default" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_OwnershipDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_OwnershipAxis_da94f5fb-aa90-4e05-874f-5f6cd3e1cd30" xlink:to="loc_srt_OwnershipDomain_da94f5fb-aa90-4e05-874f-5f6cd3e1cd30_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_OwnershipDomain_7cf5299f-be70-4834-8d7a-6e7953d5e0e9" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_OwnershipDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_OwnershipAxis_da94f5fb-aa90-4e05-874f-5f6cd3e1cd30" xlink:to="loc_srt_OwnershipDomain_7cf5299f-be70-4834-8d7a-6e7953d5e0e9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_wlkp_WestlakeChemicalCorporationMember_b0e54afd-0260-48aa-afdb-a77dedae922b" xlink:href="wlkp-20211231.xsd#wlkp_WestlakeChemicalCorporationMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_OwnershipDomain_7cf5299f-be70-4834-8d7a-6e7953d5e0e9" xlink:to="loc_wlkp_WestlakeChemicalCorporationMember_b0e54afd-0260-48aa-afdb-a77dedae922b" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_wlkp_WestlakeChemicalOpCoLPMember_be16eccb-d4c3-4c13-af63-e749762d8c33" xlink:href="wlkp-20211231.xsd#wlkp_WestlakeChemicalOpCoLPMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_OwnershipDomain_7cf5299f-be70-4834-8d7a-6e7953d5e0e9" xlink:to="loc_wlkp_WestlakeChemicalOpCoLPMember_be16eccb-d4c3-4c13-af63-e749762d8c33" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_wlkp_WestlakeChemicalPartnersLPMember_2ea27f2f-a6fb-4786-8455-06fc107311c2" xlink:href="wlkp-20211231.xsd#wlkp_WestlakeChemicalPartnersLPMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_OwnershipDomain_7cf5299f-be70-4834-8d7a-6e7953d5e0e9" xlink:to="loc_wlkp_WestlakeChemicalPartnersLPMember_2ea27f2f-a6fb-4786-8455-06fc107311c2" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.westlake.com/role/DescriptionofBusinessandSignificantAccountingPoliciesScheduleOfEstimatedUsefulLivesOfAssetsDetails" xlink:type="simple" xlink:href="wlkp-20211231.xsd#DescriptionofBusinessandSignificantAccountingPoliciesScheduleOfEstimatedUsefulLivesOfAssetsDetails"/>
  <link:definitionLink xlink:role="http://www.westlake.com/role/DescriptionofBusinessandSignificantAccountingPoliciesScheduleOfEstimatedUsefulLivesOfAssetsDetails" xlink:type="extended" id="ifa3e4e40f1dc4474b7fcaf1e0ee80e8d_DescriptionofBusinessandSignificantAccountingPoliciesScheduleOfEstimatedUsefulLivesOfAssetsDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentLineItems_dd9b111d-e9f0-4efa-954a-4c1e67faaf40" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PropertyPlantAndEquipmentLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestCostsCapitalized_986153c0-d0d4-47d2-914d-fd75548089f1" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_InterestCostsCapitalized"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_dd9b111d-e9f0-4efa-954a-4c1e67faaf40" xlink:to="loc_us-gaap_InterestCostsCapitalized_986153c0-d0d4-47d2-914d-fd75548089f1" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentUsefulLife_e55a23a9-a536-4fbc-a66b-006adf7f16b5" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PropertyPlantAndEquipmentUsefulLife"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_dd9b111d-e9f0-4efa-954a-4c1e67faaf40" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentUsefulLife_e55a23a9-a536-4fbc-a66b-006adf7f16b5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_f75bd88a-7542-4bb3-a56b-d102231a2293" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfPropertyPlantAndEquipmentTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_dd9b111d-e9f0-4efa-954a-4c1e67faaf40" xlink:to="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_f75bd88a-7542-4bb3-a56b-d102231a2293" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CounterpartyNameAxis_0e64eccc-585e-4c64-aff8-a8a97070dff4" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_CounterpartyNameAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_f75bd88a-7542-4bb3-a56b-d102231a2293" xlink:to="loc_srt_CounterpartyNameAxis_0e64eccc-585e-4c64-aff8-a8a97070dff4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RepurchaseAgreementCounterpartyNameDomain_0e64eccc-585e-4c64-aff8-a8a97070dff4_default" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RepurchaseAgreementCounterpartyNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_CounterpartyNameAxis_0e64eccc-585e-4c64-aff8-a8a97070dff4" xlink:to="loc_srt_RepurchaseAgreementCounterpartyNameDomain_0e64eccc-585e-4c64-aff8-a8a97070dff4_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RepurchaseAgreementCounterpartyNameDomain_09ef3623-0c8c-4a7f-9252-4b10dbe5a324" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RepurchaseAgreementCounterpartyNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_CounterpartyNameAxis_0e64eccc-585e-4c64-aff8-a8a97070dff4" xlink:to="loc_srt_RepurchaseAgreementCounterpartyNameDomain_09ef3623-0c8c-4a7f-9252-4b10dbe5a324" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember_2b655b6c-aa2d-4ad0-96af-a84c70d8c0e2" xlink:href="wlkp-20211231.xsd#wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RepurchaseAgreementCounterpartyNameDomain_09ef3623-0c8c-4a7f-9252-4b10dbe5a324" xlink:to="loc_wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember_2b655b6c-aa2d-4ad0-96af-a84c70d8c0e2" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_548eed24-e5be-426a-a449-9eebc74dc5c0" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_f75bd88a-7542-4bb3-a56b-d102231a2293" xlink:to="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_548eed24-e5be-426a-a449-9eebc74dc5c0" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_548eed24-e5be-426a-a449-9eebc74dc5c0_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_548eed24-e5be-426a-a449-9eebc74dc5c0" xlink:to="loc_us-gaap_RelatedPartyDomain_548eed24-e5be-426a-a449-9eebc74dc5c0_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_e8d79273-94f2-49ec-98cf-2b0c70c0c156" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_548eed24-e5be-426a-a449-9eebc74dc5c0" xlink:to="loc_us-gaap_RelatedPartyDomain_e8d79273-94f2-49ec-98cf-2b0c70c0c156" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_AffiliatedEntityMember_8e995e3f-655e-4451-8959-0132e72a7331" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_AffiliatedEntityMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyDomain_e8d79273-94f2-49ec-98cf-2b0c70c0c156" xlink:to="loc_srt_AffiliatedEntityMember_8e995e3f-655e-4451-8959-0132e72a7331" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_e934c150-586a-419d-8294-b0f8eec30976" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_f75bd88a-7542-4bb3-a56b-d102231a2293" xlink:to="loc_srt_RangeAxis_e934c150-586a-419d-8294-b0f8eec30976" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_e934c150-586a-419d-8294-b0f8eec30976_default" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_e934c150-586a-419d-8294-b0f8eec30976" xlink:to="loc_srt_RangeMember_e934c150-586a-419d-8294-b0f8eec30976_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_59c9ab80-b14d-4e05-9c0c-3eb93d0a4ce3" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_e934c150-586a-419d-8294-b0f8eec30976" xlink:to="loc_srt_RangeMember_59c9ab80-b14d-4e05-9c0c-3eb93d0a4ce3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MinimumMember_ff4f859b-0eb7-42c3-beff-8ddeff5d05e4" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_MinimumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_59c9ab80-b14d-4e05-9c0c-3eb93d0a4ce3" xlink:to="loc_srt_MinimumMember_ff4f859b-0eb7-42c3-beff-8ddeff5d05e4" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MaximumMember_42b85e4a-a85b-4f7d-bfc5-8b7a94f956b0" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_MaximumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_59c9ab80-b14d-4e05-9c0c-3eb93d0a4ce3" xlink:to="loc_srt_MaximumMember_42b85e4a-a85b-4f7d-bfc5-8b7a94f956b0" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_48c39bf1-dbbc-454c-949b-f683c7a4fb59" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PropertyPlantAndEquipmentByTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_f75bd88a-7542-4bb3-a56b-d102231a2293" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_48c39bf1-dbbc-454c-949b-f683c7a4fb59" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_48c39bf1-dbbc-454c-949b-f683c7a4fb59_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PropertyPlantAndEquipmentTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_48c39bf1-dbbc-454c-949b-f683c7a4fb59" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_48c39bf1-dbbc-454c-949b-f683c7a4fb59_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_af3b68b6-fd37-4bb6-9bc4-a2a3837bc8a9" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PropertyPlantAndEquipmentTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_48c39bf1-dbbc-454c-949b-f683c7a4fb59" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_af3b68b6-fd37-4bb6-9bc4-a2a3837bc8a9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BuildingAndBuildingImprovementsMember_792952ed-ae7d-4100-be9e-19be65649cb0" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BuildingAndBuildingImprovementsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_af3b68b6-fd37-4bb6-9bc4-a2a3837bc8a9" xlink:to="loc_us-gaap_BuildingAndBuildingImprovementsMember_792952ed-ae7d-4100-be9e-19be65649cb0" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_wlkp_PlantAndEquipmentMember_78f8b454-ad6b-4b9e-833a-caa0ac673da6" xlink:href="wlkp-20211231.xsd#wlkp_PlantAndEquipmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_af3b68b6-fd37-4bb6-9bc4-a2a3837bc8a9" xlink:to="loc_wlkp_PlantAndEquipmentMember_78f8b454-ad6b-4b9e-833a-caa0ac673da6" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_wlkp_EthylenePipelineMember_e809e860-1b5b-4728-acb9-b28b4803bc88" xlink:href="wlkp-20211231.xsd#wlkp_EthylenePipelineMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_af3b68b6-fd37-4bb6-9bc4-a2a3837bc8a9" xlink:to="loc_wlkp_EthylenePipelineMember_e809e860-1b5b-4728-acb9-b28b4803bc88" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherCapitalizedPropertyPlantAndEquipmentMember_467d1839-d2e9-4498-8207-3336b508ab2e" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherCapitalizedPropertyPlantAndEquipmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_af3b68b6-fd37-4bb6-9bc4-a2a3837bc8a9" xlink:to="loc_us-gaap_OtherCapitalizedPropertyPlantAndEquipmentMember_467d1839-d2e9-4498-8207-3336b508ab2e" xlink:type="arc" order="3"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.westlake.com/role/AgreementswithWestlakeandRelatedPartiesDetails" xlink:type="simple" xlink:href="wlkp-20211231.xsd#AgreementswithWestlakeandRelatedPartiesDetails"/>
  <link:definitionLink xlink:role="http://www.westlake.com/role/AgreementswithWestlakeandRelatedPartiesDetails" xlink:type="extended" id="ia8e90ea8f96648298222851b385ea4fd_AgreementswithWestlakeandRelatedPartiesDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LimitedPartnersCapitalAccountLineItems_dff95f30-eacc-4dfd-8b50-4750b7676d89" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LimitedPartnersCapitalAccountLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermCommitmentExcludingUnconditionalPurchaseObligationAbstract_01260777-a3d9-42b9-98f8-e4a39f2b89e6" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LongTermCommitmentExcludingUnconditionalPurchaseObligationAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountLineItems_dff95f30-eacc-4dfd-8b50-4750b7676d89" xlink:to="loc_us-gaap_LongTermCommitmentExcludingUnconditionalPurchaseObligationAbstract_01260777-a3d9-42b9-98f8-e4a39f2b89e6" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermPurchaseCommitmentPeriod_3a929650-8b04-44f2-ae19-130d7ece8019" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LongtermPurchaseCommitmentPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongTermCommitmentExcludingUnconditionalPurchaseObligationAbstract_01260777-a3d9-42b9-98f8-e4a39f2b89e6" xlink:to="loc_us-gaap_LongtermPurchaseCommitmentPeriod_3a929650-8b04-44f2-ae19-130d7ece8019" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_wlkp_LongtermPurchaseCommitmentMinimumPercentageRequired_90631964-93ce-4b2e-a7a0-d6f0353abed8" xlink:href="wlkp-20211231.xsd#wlkp_LongtermPurchaseCommitmentMinimumPercentageRequired"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongTermCommitmentExcludingUnconditionalPurchaseObligationAbstract_01260777-a3d9-42b9-98f8-e4a39f2b89e6" xlink:to="loc_wlkp_LongtermPurchaseCommitmentMinimumPercentageRequired_90631964-93ce-4b2e-a7a0-d6f0353abed8" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_wlkp_LongtermPurchaseCommitmentMaximumVolumeRequired_f22df9f4-c9bf-4b41-b522-44640ecdd62c" xlink:href="wlkp-20211231.xsd#wlkp_LongtermPurchaseCommitmentMaximumVolumeRequired"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongTermCommitmentExcludingUnconditionalPurchaseObligationAbstract_01260777-a3d9-42b9-98f8-e4a39f2b89e6" xlink:to="loc_wlkp_LongtermPurchaseCommitmentMaximumVolumeRequired_f22df9f4-c9bf-4b41-b522-44640ecdd62c" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_wlkp_PurchaseCommitmentPurchaseAgreementMass_002b2060-f2e8-4c1d-9503-32013fb44bf2" xlink:href="wlkp-20211231.xsd#wlkp_PurchaseCommitmentPurchaseAgreementMass"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongTermCommitmentExcludingUnconditionalPurchaseObligationAbstract_01260777-a3d9-42b9-98f8-e4a39f2b89e6" xlink:to="loc_wlkp_PurchaseCommitmentPurchaseAgreementMass_002b2060-f2e8-4c1d-9503-32013fb44bf2" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_wlkp_LongtermPurchaseCommitmentExchangeFeeFixedMargin_0847ed82-1f1a-4577-9078-929170e5ec09" xlink:href="wlkp-20211231.xsd#wlkp_LongtermPurchaseCommitmentExchangeFeeFixedMargin"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongTermCommitmentExcludingUnconditionalPurchaseObligationAbstract_01260777-a3d9-42b9-98f8-e4a39f2b89e6" xlink:to="loc_wlkp_LongtermPurchaseCommitmentExchangeFeeFixedMargin_0847ed82-1f1a-4577-9078-929170e5ec09" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_wlkp_RelatedPartyTransactionTermOfAgreement_5ba38e99-6367-4810-8c31-cb9fd906b5da" xlink:href="wlkp-20211231.xsd#wlkp_RelatedPartyTransactionTermOfAgreement"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongTermCommitmentExcludingUnconditionalPurchaseObligationAbstract_01260777-a3d9-42b9-98f8-e4a39f2b89e6" xlink:to="loc_wlkp_RelatedPartyTransactionTermOfAgreement_5ba38e99-6367-4810-8c31-cb9fd906b5da" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_wlkp_RelatedPartyTransactionCounterpartyDefaultPeriodOfDefaultAllowingTerminationOfAgreement_53c8b99f-3d91-4543-a8b4-83b9eb1f1cdc" xlink:href="wlkp-20211231.xsd#wlkp_RelatedPartyTransactionCounterpartyDefaultPeriodOfDefaultAllowingTerminationOfAgreement"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongTermCommitmentExcludingUnconditionalPurchaseObligationAbstract_01260777-a3d9-42b9-98f8-e4a39f2b89e6" xlink:to="loc_wlkp_RelatedPartyTransactionCounterpartyDefaultPeriodOfDefaultAllowingTerminationOfAgreement_53c8b99f-3d91-4543-a8b4-83b9eb1f1cdc" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_wlkp_LesseeLeasingArrangementsOperatingLeasesNumber_20b2b61b-c669-4af8-be68-fa73be47e75a" xlink:href="wlkp-20211231.xsd#wlkp_LesseeLeasingArrangementsOperatingLeasesNumber"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongTermCommitmentExcludingUnconditionalPurchaseObligationAbstract_01260777-a3d9-42b9-98f8-e4a39f2b89e6" xlink:to="loc_wlkp_LesseeLeasingArrangementsOperatingLeasesNumber_20b2b61b-c669-4af8-be68-fa73be47e75a" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LeaseAndRentalExpense_f6ee8b57-29f4-4b05-abc0-35e51b059484" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LeaseAndRentalExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongTermCommitmentExcludingUnconditionalPurchaseObligationAbstract_01260777-a3d9-42b9-98f8-e4a39f2b89e6" xlink:to="loc_us-gaap_LeaseAndRentalExpense_f6ee8b57-29f4-4b05-abc0-35e51b059484" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeOperatingLeaseTermOfContract_0b9a2b4f-1fb1-4396-aaac-3367c203f138" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LesseeOperatingLeaseTermOfContract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongTermCommitmentExcludingUnconditionalPurchaseObligationAbstract_01260777-a3d9-42b9-98f8-e4a39f2b89e6" xlink:to="loc_us-gaap_LesseeOperatingLeaseTermOfContract_0b9a2b4f-1fb1-4396-aaac-3367c203f138" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_wlkp_TermofInvestmentManagementAgreementwithRelatedPartyMaximum_1be5a7e9-33c7-4d1a-bc87-c8442c03bda4" xlink:href="wlkp-20211231.xsd#wlkp_TermofInvestmentManagementAgreementwithRelatedPartyMaximum"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountLineItems_dff95f30-eacc-4dfd-8b50-4750b7676d89" xlink:to="loc_wlkp_TermofInvestmentManagementAgreementwithRelatedPartyMaximum_1be5a7e9-33c7-4d1a-bc87-c8442c03bda4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_wlkp_ReceivablesunderInvestmentManagementAgreementswithRelatedPartiesCurrent_bbdef46c-00dd-41d9-9e6d-8a737b9827c5" xlink:href="wlkp-20211231.xsd#wlkp_ReceivablesunderInvestmentManagementAgreementswithRelatedPartiesCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountLineItems_dff95f30-eacc-4dfd-8b50-4750b7676d89" xlink:to="loc_wlkp_ReceivablesunderInvestmentManagementAgreementswithRelatedPartiesCurrent_bbdef46c-00dd-41d9-9e6d-8a737b9827c5" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_wlkp_LongTermPurchaseCommitmentComplianceSurchargeAmount_3dc9cc77-5c94-4272-bcc5-b3309abcff4a" xlink:href="wlkp-20211231.xsd#wlkp_LongTermPurchaseCommitmentComplianceSurchargeAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountLineItems_dff95f30-eacc-4dfd-8b50-4750b7676d89" xlink:to="loc_wlkp_LongTermPurchaseCommitmentComplianceSurchargeAmount_3dc9cc77-5c94-4272-bcc5-b3309abcff4a" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_wlkp_LongtermPurchaseCommitmentRenewalTerm_afd43072-77b5-45c9-bfc4-33d85b35e3f5" xlink:href="wlkp-20211231.xsd#wlkp_LongtermPurchaseCommitmentRenewalTerm"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountLineItems_dff95f30-eacc-4dfd-8b50-4750b7676d89" xlink:to="loc_wlkp_LongtermPurchaseCommitmentRenewalTerm_afd43072-77b5-45c9-bfc4-33d85b35e3f5" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_wlkp_LongtermPurchaseCommitmentTermsofFeeNumberOfYearsUsedToCalculateAverageExpenses_86cbe241-0735-413e-b39d-ab53d73fd19c" xlink:href="wlkp-20211231.xsd#wlkp_LongtermPurchaseCommitmentTermsofFeeNumberOfYearsUsedToCalculateAverageExpenses"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountLineItems_dff95f30-eacc-4dfd-8b50-4750b7676d89" xlink:to="loc_wlkp_LongtermPurchaseCommitmentTermsofFeeNumberOfYearsUsedToCalculateAverageExpenses_86cbe241-0735-413e-b39d-ab53d73fd19c" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfLimitedPartnersCapitalAccountByClassTable_fd22c548-7d64-486e-9ebe-a628603b8bb8" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfLimitedPartnersCapitalAccountByClassTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountLineItems_dff95f30-eacc-4dfd-8b50-4750b7676d89" xlink:to="loc_us-gaap_ScheduleOfLimitedPartnersCapitalAccountByClassTable_fd22c548-7d64-486e-9ebe-a628603b8bb8" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CounterpartyNameAxis_e2936c85-57a2-49d3-bd90-e4498defb3fa" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_CounterpartyNameAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfLimitedPartnersCapitalAccountByClassTable_fd22c548-7d64-486e-9ebe-a628603b8bb8" xlink:to="loc_srt_CounterpartyNameAxis_e2936c85-57a2-49d3-bd90-e4498defb3fa" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RepurchaseAgreementCounterpartyNameDomain_e2936c85-57a2-49d3-bd90-e4498defb3fa_default" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RepurchaseAgreementCounterpartyNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_CounterpartyNameAxis_e2936c85-57a2-49d3-bd90-e4498defb3fa" xlink:to="loc_srt_RepurchaseAgreementCounterpartyNameDomain_e2936c85-57a2-49d3-bd90-e4498defb3fa_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RepurchaseAgreementCounterpartyNameDomain_3af7f792-cf6d-4449-8e1b-607ada5bc4f3" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RepurchaseAgreementCounterpartyNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_CounterpartyNameAxis_e2936c85-57a2-49d3-bd90-e4498defb3fa" xlink:to="loc_srt_RepurchaseAgreementCounterpartyNameDomain_3af7f792-cf6d-4449-8e1b-607ada5bc4f3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_wlkp_WestlakeChemicalOpCoLPMember_5789070d-0596-4127-a38d-200891d0dbf3" xlink:href="wlkp-20211231.xsd#wlkp_WestlakeChemicalOpCoLPMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RepurchaseAgreementCounterpartyNameDomain_3af7f792-cf6d-4449-8e1b-607ada5bc4f3" xlink:to="loc_wlkp_WestlakeChemicalOpCoLPMember_5789070d-0596-4127-a38d-200891d0dbf3" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember_fe6d02a9-01ee-4e23-8ce5-eaee4ccadc72" xlink:href="wlkp-20211231.xsd#wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RepurchaseAgreementCounterpartyNameDomain_3af7f792-cf6d-4449-8e1b-607ada5bc4f3" xlink:to="loc_wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember_fe6d02a9-01ee-4e23-8ce5-eaee4ccadc72" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PartnerTypeOfPartnersCapitalAccountAxis_98b1b677-85c1-47d0-a121-8cc9658a233e" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PartnerTypeOfPartnersCapitalAccountAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfLimitedPartnersCapitalAccountByClassTable_fd22c548-7d64-486e-9ebe-a628603b8bb8" xlink:to="loc_us-gaap_PartnerTypeOfPartnersCapitalAccountAxis_98b1b677-85c1-47d0-a121-8cc9658a233e" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PartnerTypeOfPartnersCapitalAccountNameDomain_98b1b677-85c1-47d0-a121-8cc9658a233e_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PartnerTypeOfPartnersCapitalAccountNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_PartnerTypeOfPartnersCapitalAccountAxis_98b1b677-85c1-47d0-a121-8cc9658a233e" xlink:to="loc_us-gaap_PartnerTypeOfPartnersCapitalAccountNameDomain_98b1b677-85c1-47d0-a121-8cc9658a233e_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PartnerTypeOfPartnersCapitalAccountNameDomain_e5a6b544-698d-4006-b7a6-bda8eefc3a09" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PartnerTypeOfPartnersCapitalAccountNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_PartnerTypeOfPartnersCapitalAccountAxis_98b1b677-85c1-47d0-a121-8cc9658a233e" xlink:to="loc_us-gaap_PartnerTypeOfPartnersCapitalAccountNameDomain_e5a6b544-698d-4006-b7a6-bda8eefc3a09" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LimitedPartnerMember_801b0327-7376-4c89-ae1c-51ac4df0f2bb" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LimitedPartnerMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PartnerTypeOfPartnersCapitalAccountNameDomain_e5a6b544-698d-4006-b7a6-bda8eefc3a09" xlink:to="loc_us-gaap_LimitedPartnerMember_801b0327-7376-4c89-ae1c-51ac4df0f2bb" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_LegalEntityAxis_8db9b983-fcd9-4fd5-945d-45c48bbec59e" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_LegalEntityAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfLimitedPartnersCapitalAccountByClassTable_fd22c548-7d64-486e-9ebe-a628603b8bb8" xlink:to="loc_dei_LegalEntityAxis_8db9b983-fcd9-4fd5-945d-45c48bbec59e" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityDomain_8db9b983-fcd9-4fd5-945d-45c48bbec59e_default" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_EntityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_dei_LegalEntityAxis_8db9b983-fcd9-4fd5-945d-45c48bbec59e" xlink:to="loc_dei_EntityDomain_8db9b983-fcd9-4fd5-945d-45c48bbec59e_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityDomain_19c4cb3c-abed-4d19-a7af-91b47efc6c4d" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_EntityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_dei_LegalEntityAxis_8db9b983-fcd9-4fd5-945d-45c48bbec59e" xlink:to="loc_dei_EntityDomain_19c4cb3c-abed-4d19-a7af-91b47efc6c4d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_wlkp_WestlakeChemicalOpCoLPMember_76b0263d-6e65-4b5c-9d30-5a3bb92b9adf" xlink:href="wlkp-20211231.xsd#wlkp_WestlakeChemicalOpCoLPMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_19c4cb3c-abed-4d19-a7af-91b47efc6c4d" xlink:to="loc_wlkp_WestlakeChemicalOpCoLPMember_76b0263d-6e65-4b5c-9d30-5a3bb92b9adf" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember_2f8dce28-5b21-44f3-b89f-e86fe94f8b80" xlink:href="wlkp-20211231.xsd#wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_19c4cb3c-abed-4d19-a7af-91b47efc6c4d" xlink:to="loc_wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember_2f8dce28-5b21-44f3-b89f-e86fe94f8b80" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionAxis_bc99b3d3-fd29-46ec-bd62-4c1bd315fad3" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RelatedPartyTransactionAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfLimitedPartnersCapitalAccountByClassTable_fd22c548-7d64-486e-9ebe-a628603b8bb8" xlink:to="loc_us-gaap_RelatedPartyTransactionAxis_bc99b3d3-fd29-46ec-bd62-4c1bd315fad3" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionDomain_bc99b3d3-fd29-46ec-bd62-4c1bd315fad3_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RelatedPartyTransactionDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RelatedPartyTransactionAxis_bc99b3d3-fd29-46ec-bd62-4c1bd315fad3" xlink:to="loc_us-gaap_RelatedPartyTransactionDomain_bc99b3d3-fd29-46ec-bd62-4c1bd315fad3_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionDomain_91ad047c-1e54-4e81-a667-a17b9653234a" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RelatedPartyTransactionDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RelatedPartyTransactionAxis_bc99b3d3-fd29-46ec-bd62-4c1bd315fad3" xlink:to="loc_us-gaap_RelatedPartyTransactionDomain_91ad047c-1e54-4e81-a667-a17b9653234a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_wlkp_ServicesAndSecondmentAgreementMember_d179dc6c-0d05-4f36-a003-dab80d4cf0d0" xlink:href="wlkp-20211231.xsd#wlkp_ServicesAndSecondmentAgreementMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionDomain_91ad047c-1e54-4e81-a667-a17b9653234a" xlink:to="loc_wlkp_ServicesAndSecondmentAgreementMember_d179dc6c-0d05-4f36-a003-dab80d4cf0d0" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_wlkp_SiteLeaseAgreementMember_12c7ed9b-5e58-427c-8991-5a66e1d453f5" xlink:href="wlkp-20211231.xsd#wlkp_SiteLeaseAgreementMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionDomain_91ad047c-1e54-4e81-a667-a17b9653234a" xlink:to="loc_wlkp_SiteLeaseAgreementMember_12c7ed9b-5e58-427c-8991-5a66e1d453f5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_wlkp_EthyleneSalesAgreementMember_4e793b81-0892-42cc-b3b0-2d63b5723d09" xlink:href="wlkp-20211231.xsd#wlkp_EthyleneSalesAgreementMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionDomain_91ad047c-1e54-4e81-a667-a17b9653234a" xlink:to="loc_wlkp_EthyleneSalesAgreementMember_4e793b81-0892-42cc-b3b0-2d63b5723d09" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_wlkp_FeedstockSupplyAgreementMember_b80f26c7-777f-4aaf-8f4c-8809b9b885d6" xlink:href="wlkp-20211231.xsd#wlkp_FeedstockSupplyAgreementMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionDomain_91ad047c-1e54-4e81-a667-a17b9653234a" xlink:to="loc_wlkp_FeedstockSupplyAgreementMember_b80f26c7-777f-4aaf-8f4c-8809b9b885d6" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_wlkp_ExcessProductionOptionMember_350b1294-1518-4465-b693-b12c71d2b421" xlink:href="wlkp-20211231.xsd#wlkp_ExcessProductionOptionMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionDomain_91ad047c-1e54-4e81-a667-a17b9653234a" xlink:to="loc_wlkp_ExcessProductionOptionMember_350b1294-1518-4465-b693-b12c71d2b421" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_49cc86d4-99d2-4310-9365-ea1c78b543c7" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfLimitedPartnersCapitalAccountByClassTable_fd22c548-7d64-486e-9ebe-a628603b8bb8" xlink:to="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_49cc86d4-99d2-4310-9365-ea1c78b543c7" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_49cc86d4-99d2-4310-9365-ea1c78b543c7_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_49cc86d4-99d2-4310-9365-ea1c78b543c7" xlink:to="loc_us-gaap_RelatedPartyDomain_49cc86d4-99d2-4310-9365-ea1c78b543c7_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_478eda82-1671-48aa-b59d-d0c08ab64bda" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_49cc86d4-99d2-4310-9365-ea1c78b543c7" xlink:to="loc_us-gaap_RelatedPartyDomain_478eda82-1671-48aa-b59d-d0c08ab64bda" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InvesteeMember_de426df1-2281-4af1-9273-b0589849bc55" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_InvesteeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyDomain_478eda82-1671-48aa-b59d-d0c08ab64bda" xlink:to="loc_us-gaap_InvesteeMember_de426df1-2281-4af1-9273-b0589849bc55" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_OwnershipAxis_c7eff605-2f25-4008-b3d4-171d3e396e98" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_OwnershipAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfLimitedPartnersCapitalAccountByClassTable_fd22c548-7d64-486e-9ebe-a628603b8bb8" xlink:to="loc_srt_OwnershipAxis_c7eff605-2f25-4008-b3d4-171d3e396e98" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_OwnershipDomain_c7eff605-2f25-4008-b3d4-171d3e396e98_default" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_OwnershipDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_OwnershipAxis_c7eff605-2f25-4008-b3d4-171d3e396e98" xlink:to="loc_srt_OwnershipDomain_c7eff605-2f25-4008-b3d4-171d3e396e98_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_OwnershipDomain_7e3b6c6f-bad4-4228-830b-1a8a0cff1c7a" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_OwnershipDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_OwnershipAxis_c7eff605-2f25-4008-b3d4-171d3e396e98" xlink:to="loc_srt_OwnershipDomain_7e3b6c6f-bad4-4228-830b-1a8a0cff1c7a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_wlkp_WestlakeChemicalOpCoLPMember_8c63e0ae-4f01-4bc7-8979-686fbd592e21" xlink:href="wlkp-20211231.xsd#wlkp_WestlakeChemicalOpCoLPMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_OwnershipDomain_7e3b6c6f-bad4-4228-830b-1a8a0cff1c7a" xlink:to="loc_wlkp_WestlakeChemicalOpCoLPMember_8c63e0ae-4f01-4bc7-8979-686fbd592e21" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.westlake.com/role/DeferredChargesandOtherAssetsScheduleOfIntangibleandOtherAssetsDetails" xlink:type="simple" xlink:href="wlkp-20211231.xsd#DeferredChargesandOtherAssetsScheduleOfIntangibleandOtherAssetsDetails"/>
  <link:definitionLink xlink:role="http://www.westlake.com/role/DeferredChargesandOtherAssetsScheduleOfIntangibleandOtherAssetsDetails" xlink:type="extended" id="ib2e12ed27b804af1ab9472ba3e5b775f_DeferredChargesandOtherAssetsScheduleOfIntangibleandOtherAssetsDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_7ed98702-708b-405e-84b8-04e3f7ea7af5" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdjustmentForAmortization_30ebe386-1839-4622-9280-2d7b7169c70e" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AdjustmentForAmortization"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_7ed98702-708b-405e-84b8-04e3f7ea7af5" xlink:to="loc_us-gaap_AdjustmentForAmortization_30ebe386-1839-4622-9280-2d7b7169c70e" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsRemainingAmortizationPeriod1_276fec8f-0817-44e0-b1e6-aee55e45dbd8" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsRemainingAmortizationPeriod1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_7ed98702-708b-405e-84b8-04e3f7ea7af5" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsRemainingAmortizationPeriod1_276fec8f-0817-44e0-b1e6-aee55e45dbd8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable_a24ef38e-5c89-41e5-a430-2453a9be5bc1" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_7ed98702-708b-405e-84b8-04e3f7ea7af5" xlink:to="loc_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable_a24ef38e-5c89-41e5-a430-2453a9be5bc1" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_2e1f3edc-fcc5-4554-8c11-e3361c43f4b5" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable_a24ef38e-5c89-41e5-a430-2453a9be5bc1" xlink:to="loc_srt_RangeAxis_2e1f3edc-fcc5-4554-8c11-e3361c43f4b5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_2e1f3edc-fcc5-4554-8c11-e3361c43f4b5_default" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_2e1f3edc-fcc5-4554-8c11-e3361c43f4b5" xlink:to="loc_srt_RangeMember_2e1f3edc-fcc5-4554-8c11-e3361c43f4b5_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_2034a2f1-7bc1-4a93-a365-dfbea78f3fef" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_2e1f3edc-fcc5-4554-8c11-e3361c43f4b5" xlink:to="loc_srt_RangeMember_2034a2f1-7bc1-4a93-a365-dfbea78f3fef" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MinimumMember_cd5d6860-6a1d-42c7-acfe-3ddab34f6469" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_MinimumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_2034a2f1-7bc1-4a93-a365-dfbea78f3fef" xlink:to="loc_srt_MinimumMember_cd5d6860-6a1d-42c7-acfe-3ddab34f6469" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MaximumMember_207f1f16-cbb3-4a74-8b76-f6f62cc111db" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_MaximumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_2034a2f1-7bc1-4a93-a365-dfbea78f3fef" xlink:to="loc_srt_MaximumMember_207f1f16-cbb3-4a74-8b76-f6f62cc111db" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BalanceSheetLocationAxis_c855b138-c107-4dc6-b0a4-ec11216ff6c0" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BalanceSheetLocationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable_a24ef38e-5c89-41e5-a430-2453a9be5bc1" xlink:to="loc_us-gaap_BalanceSheetLocationAxis_c855b138-c107-4dc6-b0a4-ec11216ff6c0" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BalanceSheetLocationDomain_c855b138-c107-4dc6-b0a4-ec11216ff6c0_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BalanceSheetLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BalanceSheetLocationAxis_c855b138-c107-4dc6-b0a4-ec11216ff6c0" xlink:to="loc_us-gaap_BalanceSheetLocationDomain_c855b138-c107-4dc6-b0a4-ec11216ff6c0_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BalanceSheetLocationDomain_a961922a-172a-451e-a8ef-072e8b4810de" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BalanceSheetLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BalanceSheetLocationAxis_c855b138-c107-4dc6-b0a4-ec11216ff6c0" xlink:to="loc_us-gaap_BalanceSheetLocationDomain_a961922a-172a-451e-a8ef-072e8b4810de" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherAssetsMember_332cbe43-bb0e-454b-a136-d84dd39876c1" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherAssetsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BalanceSheetLocationDomain_a961922a-172a-451e-a8ef-072e8b4810de" xlink:to="loc_us-gaap_OtherAssetsMember_332cbe43-bb0e-454b-a136-d84dd39876c1" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.westlake.com/role/LongTermDebtScheduleofLongtermDebtDetails" xlink:type="simple" xlink:href="wlkp-20211231.xsd#LongTermDebtScheduleofLongtermDebtDetails"/>
  <link:definitionLink xlink:role="http://www.westlake.com/role/LongTermDebtScheduleofLongtermDebtDetails" xlink:type="extended" id="i519afa17470a44dab0540308e44d496b_LongTermDebtScheduleofLongtermDebtDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionLineItems_cb1a223e-2ee4-4018-b293-8470123418d0" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RelatedPartyTransactionLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DueToRelatedPartiesNoncurrent_93f26029-5545-4cd5-8969-4263caa17206" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DueToRelatedPartiesNoncurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_cb1a223e-2ee4-4018-b293-8470123418d0" xlink:to="loc_us-gaap_DueToRelatedPartiesNoncurrent_93f26029-5545-4cd5-8969-4263caa17206" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentBasisSpreadOnVariableRate1_38c6c0f4-a8df-4681-98c2-8906652f9e00" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentBasisSpreadOnVariableRate1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_cb1a223e-2ee4-4018-b293-8470123418d0" xlink:to="loc_us-gaap_DebtInstrumentBasisSpreadOnVariableRate1_38c6c0f4-a8df-4681-98c2-8906652f9e00" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity_e85de08b-e026-4a80-ae10-d84c167fee9d" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_cb1a223e-2ee4-4018-b293-8470123418d0" xlink:to="loc_us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity_e85de08b-e026-4a80-ae10-d84c167fee9d" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentsToAcquireLimitedPartnershipInterests_7d4f4ca7-aa2e-45fc-9efe-eb243c15dcb1" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PaymentsToAcquireLimitedPartnershipInterests"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_cb1a223e-2ee4-4018-b293-8470123418d0" xlink:to="loc_us-gaap_PaymentsToAcquireLimitedPartnershipInterests_7d4f4ca7-aa2e-45fc-9efe-eb243c15dcb1" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_wlkp_LimitedLiabilityCompanyLLCorLimitedPartnershipLPMembersorLimitedPartnersAdditionalOwnershipInterest_fbdb29e6-3de6-48b5-a75a-94d450219f78" xlink:href="wlkp-20211231.xsd#wlkp_LimitedLiabilityCompanyLLCorLimitedPartnershipLPMembersorLimitedPartnersAdditionalOwnershipInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_cb1a223e-2ee4-4018-b293-8470123418d0" xlink:to="loc_wlkp_LimitedLiabilityCompanyLLCorLimitedPartnershipLPMembersorLimitedPartnersAdditionalOwnershipInterest_fbdb29e6-3de6-48b5-a75a-94d450219f78" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_wlkp_MaximumConsolidatedLeverageRatioDuringOneYearFollowingAcquisitions_087af67e-c66e-473a-9d3d-560f44c401f0" xlink:href="wlkp-20211231.xsd#wlkp_MaximumConsolidatedLeverageRatioDuringOneYearFollowingAcquisitions"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_cb1a223e-2ee4-4018-b293-8470123418d0" xlink:to="loc_wlkp_MaximumConsolidatedLeverageRatioDuringOneYearFollowingAcquisitions_087af67e-c66e-473a-9d3d-560f44c401f0" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_wlkp_LeverageCapitalRatioRequiredDuringOtherPeriods_6b0999f5-53d1-4686-b6b1-8874c85749c1" xlink:href="wlkp-20211231.xsd#wlkp_LeverageCapitalRatioRequiredDuringOtherPeriods"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_cb1a223e-2ee4-4018-b293-8470123418d0" xlink:to="loc_wlkp_LeverageCapitalRatioRequiredDuringOtherPeriods_6b0999f5-53d1-4686-b6b1-8874c85749c1" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProceedsFromRelatedPartyDebt_b0717697-a1f2-4f56-9802-9bdc6048a3a4" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ProceedsFromRelatedPartyDebt"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_cb1a223e-2ee4-4018-b293-8470123418d0" xlink:to="loc_us-gaap_ProceedsFromRelatedPartyDebt_b0717697-a1f2-4f56-9802-9bdc6048a3a4" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtWeightedAverageInterestRate_36312b6a-a88e-47e2-a09a-7ea8d13d9fbf" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LongtermDebtWeightedAverageInterestRate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_cb1a223e-2ee4-4018-b293-8470123418d0" xlink:to="loc_us-gaap_LongtermDebtWeightedAverageInterestRate_36312b6a-a88e-47e2-a09a-7ea8d13d9fbf" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_3f60383b-1fe6-4ed0-a948-0ac4e432fb5c" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_cb1a223e-2ee4-4018-b293-8470123418d0" xlink:to="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_3f60383b-1fe6-4ed0-a948-0ac4e432fb5c" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CounterpartyNameAxis_68c2587b-1fb3-4fb6-ba25-b30af024bd3e" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_CounterpartyNameAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_3f60383b-1fe6-4ed0-a948-0ac4e432fb5c" xlink:to="loc_srt_CounterpartyNameAxis_68c2587b-1fb3-4fb6-ba25-b30af024bd3e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RepurchaseAgreementCounterpartyNameDomain_68c2587b-1fb3-4fb6-ba25-b30af024bd3e_default" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RepurchaseAgreementCounterpartyNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_CounterpartyNameAxis_68c2587b-1fb3-4fb6-ba25-b30af024bd3e" xlink:to="loc_srt_RepurchaseAgreementCounterpartyNameDomain_68c2587b-1fb3-4fb6-ba25-b30af024bd3e_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RepurchaseAgreementCounterpartyNameDomain_15abbb92-92c0-499c-95af-300e835678f2" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RepurchaseAgreementCounterpartyNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_CounterpartyNameAxis_68c2587b-1fb3-4fb6-ba25-b30af024bd3e" xlink:to="loc_srt_RepurchaseAgreementCounterpartyNameDomain_15abbb92-92c0-499c-95af-300e835678f2" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember_1e220842-dbc4-4492-8e30-93183016437b" xlink:href="wlkp-20211231.xsd#wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RepurchaseAgreementCounterpartyNameDomain_15abbb92-92c0-499c-95af-300e835678f2" xlink:to="loc_wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember_1e220842-dbc4-4492-8e30-93183016437b" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_wlkp_WestlakeChemicalOpCoLPMember_a195cf17-4432-4d0e-b82b-468c10aa05e9" xlink:href="wlkp-20211231.xsd#wlkp_WestlakeChemicalOpCoLPMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RepurchaseAgreementCounterpartyNameDomain_15abbb92-92c0-499c-95af-300e835678f2" xlink:to="loc_wlkp_WestlakeChemicalOpCoLPMember_a195cf17-4432-4d0e-b82b-468c10aa05e9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_e3fd11bf-e4be-4c8b-b208-4710df1b3076" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_3f60383b-1fe6-4ed0-a948-0ac4e432fb5c" xlink:to="loc_srt_RangeAxis_e3fd11bf-e4be-4c8b-b208-4710df1b3076" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_e3fd11bf-e4be-4c8b-b208-4710df1b3076_default" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_e3fd11bf-e4be-4c8b-b208-4710df1b3076" xlink:to="loc_srt_RangeMember_e3fd11bf-e4be-4c8b-b208-4710df1b3076_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_9d037271-300d-4beb-a063-df50dbfb5a7b" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_e3fd11bf-e4be-4c8b-b208-4710df1b3076" xlink:to="loc_srt_RangeMember_9d037271-300d-4beb-a063-df50dbfb5a7b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MinimumMember_6baebdd2-2d9a-4e06-8675-df7f6b49334e" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_MinimumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_9d037271-300d-4beb-a063-df50dbfb5a7b" xlink:to="loc_srt_MinimumMember_6baebdd2-2d9a-4e06-8675-df7f6b49334e" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MaximumMember_4b12235f-140a-4043-ac67-2a17711d3691" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_MaximumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_9d037271-300d-4beb-a063-df50dbfb5a7b" xlink:to="loc_srt_MaximumMember_4b12235f-140a-4043-ac67-2a17711d3691" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_24ec8d57-0ece-447d-a35a-f32289b13039" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_3f60383b-1fe6-4ed0-a948-0ac4e432fb5c" xlink:to="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_24ec8d57-0ece-447d-a35a-f32289b13039" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_24ec8d57-0ece-447d-a35a-f32289b13039_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_24ec8d57-0ece-447d-a35a-f32289b13039" xlink:to="loc_us-gaap_RelatedPartyDomain_24ec8d57-0ece-447d-a35a-f32289b13039_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_c211e6eb-70d7-4ed3-824f-dfaa46466514" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_24ec8d57-0ece-447d-a35a-f32289b13039" xlink:to="loc_us-gaap_RelatedPartyDomain_c211e6eb-70d7-4ed3-824f-dfaa46466514" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LimitedPartnerMember_188542d8-e5d5-4110-ba5f-e4126ef40a6a" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LimitedPartnerMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyDomain_c211e6eb-70d7-4ed3-824f-dfaa46466514" xlink:to="loc_us-gaap_LimitedPartnerMember_188542d8-e5d5-4110-ba5f-e4126ef40a6a" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_AffiliatedEntityMember_693ea5e7-31d8-432d-be00-594f66c4fc8d" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_AffiliatedEntityMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyDomain_c211e6eb-70d7-4ed3-824f-dfaa46466514" xlink:to="loc_srt_AffiliatedEntityMember_693ea5e7-31d8-432d-be00-594f66c4fc8d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeAxis_2132e299-6a73-442e-83f1-0da1f0c3571d" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LongtermDebtTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_3f60383b-1fe6-4ed0-a948-0ac4e432fb5c" xlink:to="loc_us-gaap_LongtermDebtTypeAxis_2132e299-6a73-442e-83f1-0da1f0c3571d" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_2132e299-6a73-442e-83f1-0da1f0c3571d_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_2132e299-6a73-442e-83f1-0da1f0c3571d" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_2132e299-6a73-442e-83f1-0da1f0c3571d_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_5ac398ea-b336-4a71-9e30-12ed9087420f" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_2132e299-6a73-442e-83f1-0da1f0c3571d" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_5ac398ea-b336-4a71-9e30-12ed9087420f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditMember_eccbffb2-5346-4c25-b738-48051614e847" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LineOfCreditMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_5ac398ea-b336-4a71-9e30-12ed9087420f" xlink:to="loc_us-gaap_LineOfCreditMember_eccbffb2-5346-4c25-b738-48051614e847" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_wlkp_SeniorUnsecuredRevolvingCreditFacilityMember_79c91398-3a55-4fef-aafe-1bbd51646833" xlink:href="wlkp-20211231.xsd#wlkp_SeniorUnsecuredRevolvingCreditFacilityMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_5ac398ea-b336-4a71-9e30-12ed9087420f" xlink:to="loc_wlkp_SeniorUnsecuredRevolvingCreditFacilityMember_79c91398-3a55-4fef-aafe-1bbd51646833" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentAxis_d2a072b0-f0bd-42c8-8d1b-9291688b397e" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_3f60383b-1fe6-4ed0-a948-0ac4e432fb5c" xlink:to="loc_us-gaap_DebtInstrumentAxis_d2a072b0-f0bd-42c8-8d1b-9291688b397e" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_d2a072b0-f0bd-42c8-8d1b-9291688b397e_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DebtInstrumentAxis_d2a072b0-f0bd-42c8-8d1b-9291688b397e" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_d2a072b0-f0bd-42c8-8d1b-9291688b397e_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_281df833-356a-4e67-aa99-3f1401d29df9" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DebtInstrumentAxis_d2a072b0-f0bd-42c8-8d1b-9291688b397e" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_281df833-356a-4e67-aa99-3f1401d29df9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_wlkp_OpCoRevolverMember_55fa6a81-8577-4163-8e54-7eac41e200a4" xlink:href="wlkp-20211231.xsd#wlkp_OpCoRevolverMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_281df833-356a-4e67-aa99-3f1401d29df9" xlink:to="loc_wlkp_OpCoRevolverMember_55fa6a81-8577-4163-8e54-7eac41e200a4" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_wlkp_MLPRevolverMember_c4a33ce9-8a4b-44cf-95db-e2f07c9c45c3" xlink:href="wlkp-20211231.xsd#wlkp_MLPRevolverMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_281df833-356a-4e67-aa99-3f1401d29df9" xlink:to="loc_wlkp_MLPRevolverMember_c4a33ce9-8a4b-44cf-95db-e2f07c9c45c3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_LegalEntityAxis_bfeeaf36-1a04-44f1-9bc2-106613a7d8b0" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_LegalEntityAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_3f60383b-1fe6-4ed0-a948-0ac4e432fb5c" xlink:to="loc_dei_LegalEntityAxis_bfeeaf36-1a04-44f1-9bc2-106613a7d8b0" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityDomain_bfeeaf36-1a04-44f1-9bc2-106613a7d8b0_default" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_EntityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_dei_LegalEntityAxis_bfeeaf36-1a04-44f1-9bc2-106613a7d8b0" xlink:to="loc_dei_EntityDomain_bfeeaf36-1a04-44f1-9bc2-106613a7d8b0_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityDomain_656d3399-e095-4832-b962-ba3e7c30bae8" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_EntityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_dei_LegalEntityAxis_bfeeaf36-1a04-44f1-9bc2-106613a7d8b0" xlink:to="loc_dei_EntityDomain_656d3399-e095-4832-b962-ba3e7c30bae8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_wlkp_WestlakeChemicalOpCoLPMember_61a4111b-2d0b-4b1d-abc8-fbc83a1145a4" xlink:href="wlkp-20211231.xsd#wlkp_WestlakeChemicalOpCoLPMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_656d3399-e095-4832-b962-ba3e7c30bae8" xlink:to="loc_wlkp_WestlakeChemicalOpCoLPMember_61a4111b-2d0b-4b1d-abc8-fbc83a1145a4" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_VariableRateAxis_11d19f6c-74d1-4642-8186-7d2806cd59f2" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_VariableRateAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_3f60383b-1fe6-4ed0-a948-0ac4e432fb5c" xlink:to="loc_us-gaap_VariableRateAxis_11d19f6c-74d1-4642-8186-7d2806cd59f2" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_VariableRateDomain_11d19f6c-74d1-4642-8186-7d2806cd59f2_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_VariableRateDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_VariableRateAxis_11d19f6c-74d1-4642-8186-7d2806cd59f2" xlink:to="loc_us-gaap_VariableRateDomain_11d19f6c-74d1-4642-8186-7d2806cd59f2_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_VariableRateDomain_12e4f21f-d515-4aef-8beb-4cc4061e5e00" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_VariableRateDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_VariableRateAxis_11d19f6c-74d1-4642-8186-7d2806cd59f2" xlink:to="loc_us-gaap_VariableRateDomain_12e4f21f-d515-4aef-8beb-4cc4061e5e00" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LondonInterbankOfferedRateLIBORMember_38a2cb3b-c87a-43fe-b453-0421b7504d37" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LondonInterbankOfferedRateLIBORMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_VariableRateDomain_12e4f21f-d515-4aef-8beb-4cc4061e5e00" xlink:to="loc_us-gaap_LondonInterbankOfferedRateLIBORMember_38a2cb3b-c87a-43fe-b453-0421b7504d37" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.westlake.com/role/DistributionsandNetIncomePerLimitedPartnerUnitNarrativeDetails" xlink:type="simple" xlink:href="wlkp-20211231.xsd#DistributionsandNetIncomePerLimitedPartnerUnitNarrativeDetails"/>
  <link:definitionLink xlink:role="http://www.westlake.com/role/DistributionsandNetIncomePerLimitedPartnerUnitNarrativeDetails" xlink:type="extended" id="i7638ca11ce3e4d7782b412c2efd500c9_DistributionsandNetIncomePerLimitedPartnerUnitNarrativeDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventLineItems_3d5f222a-b97a-4e3e-ad6f-8c200831a59a" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SubsequentEventLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DistributionMadeToLimitedPartnerDistributionsDeclaredPerUnit_005c18bb-501a-4b3f-864c-ac681043a35e" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DistributionMadeToLimitedPartnerDistributionsDeclaredPerUnit"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventLineItems_3d5f222a-b97a-4e3e-ad6f-8c200831a59a" xlink:to="loc_us-gaap_DistributionMadeToLimitedPartnerDistributionsDeclaredPerUnit_005c18bb-501a-4b3f-864c-ac681043a35e" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_wlkp_IncentiveDistributionRightsTargetDistributionPerUnitRequiringMarginalPercentageDistributiontoIDRHolders_1dbbe07a-d736-4406-b028-10c3f79092fa" xlink:href="wlkp-20211231.xsd#wlkp_IncentiveDistributionRightsTargetDistributionPerUnitRequiringMarginalPercentageDistributiontoIDRHolders"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventLineItems_3d5f222a-b97a-4e3e-ad6f-8c200831a59a" xlink:to="loc_wlkp_IncentiveDistributionRightsTargetDistributionPerUnitRequiringMarginalPercentageDistributiontoIDRHolders_1dbbe07a-d736-4406-b028-10c3f79092fa" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventTable_ce744bca-991e-4d4f-8471-75173ccadedf" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SubsequentEventTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_SubsequentEventLineItems_3d5f222a-b97a-4e3e-ad6f-8c200831a59a" xlink:to="loc_us-gaap_SubsequentEventTable_ce744bca-991e-4d4f-8471-75173ccadedf" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LimitedPartnersCapitalAccountByClassAxis_5c6370d6-be0b-47ea-bcef-403cac2413e0" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LimitedPartnersCapitalAccountByClassAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_SubsequentEventTable_ce744bca-991e-4d4f-8471-75173ccadedf" xlink:to="loc_us-gaap_LimitedPartnersCapitalAccountByClassAxis_5c6370d6-be0b-47ea-bcef-403cac2413e0" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_5c6370d6-be0b-47ea-bcef-403cac2413e0_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LimitedPartnersCapitalAccountClassDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountByClassAxis_5c6370d6-be0b-47ea-bcef-403cac2413e0" xlink:to="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_5c6370d6-be0b-47ea-bcef-403cac2413e0_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_f193e530-972e-4b34-97b2-ffbedd867bd8" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LimitedPartnersCapitalAccountClassDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountByClassAxis_5c6370d6-be0b-47ea-bcef-403cac2413e0" xlink:to="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_f193e530-972e-4b34-97b2-ffbedd867bd8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_wlkp_CommonAndSubordinatedUnitsMember_41a804db-da6e-4f97-beff-1b72932a9988" xlink:href="wlkp-20211231.xsd#wlkp_CommonAndSubordinatedUnitsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_f193e530-972e-4b34-97b2-ffbedd867bd8" xlink:to="loc_wlkp_CommonAndSubordinatedUnitsMember_41a804db-da6e-4f97-beff-1b72932a9988" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DistributionsMadeToMemberOrLimitedPartnerByDistributionTypeAxis_4af79c92-b317-48a5-b37c-ce585edabf07" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DistributionsMadeToMemberOrLimitedPartnerByDistributionTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_SubsequentEventTable_ce744bca-991e-4d4f-8471-75173ccadedf" xlink:to="loc_us-gaap_DistributionsMadeToMemberOrLimitedPartnerByDistributionTypeAxis_4af79c92-b317-48a5-b37c-ce585edabf07" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DistributionTypeDomain_4af79c92-b317-48a5-b37c-ce585edabf07_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DistributionTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DistributionsMadeToMemberOrLimitedPartnerByDistributionTypeAxis_4af79c92-b317-48a5-b37c-ce585edabf07" xlink:to="loc_us-gaap_DistributionTypeDomain_4af79c92-b317-48a5-b37c-ce585edabf07_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DistributionTypeDomain_4c770d75-675d-4282-9178-a5d513761772" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DistributionTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DistributionsMadeToMemberOrLimitedPartnerByDistributionTypeAxis_4af79c92-b317-48a5-b37c-ce585edabf07" xlink:to="loc_us-gaap_DistributionTypeDomain_4c770d75-675d-4282-9178-a5d513761772" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashDistributionMember_67b71bbe-5152-4f3a-894f-1301937db83e" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CashDistributionMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DistributionTypeDomain_4c770d75-675d-4282-9178-a5d513761772" xlink:to="loc_us-gaap_CashDistributionMember_67b71bbe-5152-4f3a-894f-1301937db83e" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventTypeAxis_c8ef1625-4b44-4d3e-996d-ad85e91dee52" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SubsequentEventTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_SubsequentEventTable_ce744bca-991e-4d4f-8471-75173ccadedf" xlink:to="loc_us-gaap_SubsequentEventTypeAxis_c8ef1625-4b44-4d3e-996d-ad85e91dee52" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventTypeDomain_c8ef1625-4b44-4d3e-996d-ad85e91dee52_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SubsequentEventTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_SubsequentEventTypeAxis_c8ef1625-4b44-4d3e-996d-ad85e91dee52" xlink:to="loc_us-gaap_SubsequentEventTypeDomain_c8ef1625-4b44-4d3e-996d-ad85e91dee52_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventTypeDomain_42df7507-da1b-432b-866b-c8c357e849d0" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SubsequentEventTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_SubsequentEventTypeAxis_c8ef1625-4b44-4d3e-996d-ad85e91dee52" xlink:to="loc_us-gaap_SubsequentEventTypeDomain_42df7507-da1b-432b-866b-c8c357e849d0" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventMember_3ef309a2-8d54-4f9d-b813-46e14b1f0636" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SubsequentEventMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventTypeDomain_42df7507-da1b-432b-866b-c8c357e849d0" xlink:to="loc_us-gaap_SubsequentEventMember_3ef309a2-8d54-4f9d-b813-46e14b1f0636" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.westlake.com/role/DistributionsandNetIncomePerLimitedPartnerUnitIncentiveDistributionRightsDetails" xlink:type="simple" xlink:href="wlkp-20211231.xsd#DistributionsandNetIncomePerLimitedPartnerUnitIncentiveDistributionRightsDetails"/>
  <link:definitionLink xlink:role="http://www.westlake.com/role/DistributionsandNetIncomePerLimitedPartnerUnitIncentiveDistributionRightsDetails" xlink:type="extended" id="i25115f2a3b5d402a8632ff9ded4e7866_DistributionsandNetIncomePerLimitedPartnerUnitIncentiveDistributionRightsDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DistributionMadeToLimitedPartnerLineItems_9ac4a704-ca44-4e08-985b-6445804ebc28" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DistributionMadeToLimitedPartnerLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_wlkp_IncentiveDistributionMarginalPercentageInterestinDistributions_4f516097-5e63-4d07-aac1-398418267c8f" xlink:href="wlkp-20211231.xsd#wlkp_IncentiveDistributionMarginalPercentageInterestinDistributions"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DistributionMadeToLimitedPartnerLineItems_9ac4a704-ca44-4e08-985b-6445804ebc28" xlink:to="loc_wlkp_IncentiveDistributionMarginalPercentageInterestinDistributions_4f516097-5e63-4d07-aac1-398418267c8f" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_wlkp_IncentiveDistributionQuarterlyDistributionPerUnitDistributionThreshold_3d42c12b-1b2f-4cf1-9651-d519f5b43909" xlink:href="wlkp-20211231.xsd#wlkp_IncentiveDistributionQuarterlyDistributionPerUnitDistributionThreshold"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DistributionMadeToLimitedPartnerLineItems_9ac4a704-ca44-4e08-985b-6445804ebc28" xlink:to="loc_wlkp_IncentiveDistributionQuarterlyDistributionPerUnitDistributionThreshold_3d42c12b-1b2f-4cf1-9651-d519f5b43909" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DistributionsMadeToLimitedPartnerTable_8edb3953-5c33-4d8b-92d8-d57e1f09c4db" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DistributionsMadeToLimitedPartnerTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DistributionMadeToLimitedPartnerLineItems_9ac4a704-ca44-4e08-985b-6445804ebc28" xlink:to="loc_us-gaap_DistributionsMadeToLimitedPartnerTable_8edb3953-5c33-4d8b-92d8-d57e1f09c4db" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_74d7b656-b9f4-4df3-869a-728e242d41f3" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DistributionsMadeToLimitedPartnerTable_8edb3953-5c33-4d8b-92d8-d57e1f09c4db" xlink:to="loc_srt_RangeAxis_74d7b656-b9f4-4df3-869a-728e242d41f3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_74d7b656-b9f4-4df3-869a-728e242d41f3_default" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_74d7b656-b9f4-4df3-869a-728e242d41f3" xlink:to="loc_srt_RangeMember_74d7b656-b9f4-4df3-869a-728e242d41f3_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_af2d0bf2-896e-451e-aae4-cd18c53ecee0" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_74d7b656-b9f4-4df3-869a-728e242d41f3" xlink:to="loc_srt_RangeMember_af2d0bf2-896e-451e-aae4-cd18c53ecee0" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MinimumMember_47dfe076-f46c-4094-bae9-8f541cd4f3b4" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_MinimumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_af2d0bf2-896e-451e-aae4-cd18c53ecee0" xlink:to="loc_srt_MinimumMember_47dfe076-f46c-4094-bae9-8f541cd4f3b4" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MaximumMember_86c522ba-1914-43d6-9082-1cddf1e62c49" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_MaximumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_af2d0bf2-896e-451e-aae4-cd18c53ecee0" xlink:to="loc_srt_MaximumMember_86c522ba-1914-43d6-9082-1cddf1e62c49" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DistributionsMadeToMemberOrLimitedPartnerByDistributionTypeAxis_90bca229-2c01-43c1-b1a8-677420052ab3" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DistributionsMadeToMemberOrLimitedPartnerByDistributionTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DistributionsMadeToLimitedPartnerTable_8edb3953-5c33-4d8b-92d8-d57e1f09c4db" xlink:to="loc_us-gaap_DistributionsMadeToMemberOrLimitedPartnerByDistributionTypeAxis_90bca229-2c01-43c1-b1a8-677420052ab3" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DistributionTypeDomain_90bca229-2c01-43c1-b1a8-677420052ab3_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DistributionTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DistributionsMadeToMemberOrLimitedPartnerByDistributionTypeAxis_90bca229-2c01-43c1-b1a8-677420052ab3" xlink:to="loc_us-gaap_DistributionTypeDomain_90bca229-2c01-43c1-b1a8-677420052ab3_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DistributionTypeDomain_2e082878-ed85-44c9-96ee-c8d1a421d491" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DistributionTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DistributionsMadeToMemberOrLimitedPartnerByDistributionTypeAxis_90bca229-2c01-43c1-b1a8-677420052ab3" xlink:to="loc_us-gaap_DistributionTypeDomain_2e082878-ed85-44c9-96ee-c8d1a421d491" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_wlkp_CashDistributionTrancheOneMember_ba081ca8-e796-448a-bc60-5ae23b884038" xlink:href="wlkp-20211231.xsd#wlkp_CashDistributionTrancheOneMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DistributionTypeDomain_2e082878-ed85-44c9-96ee-c8d1a421d491" xlink:to="loc_wlkp_CashDistributionTrancheOneMember_ba081ca8-e796-448a-bc60-5ae23b884038" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_wlkp_CashDistributionTrancheTwoMember_6cb1678d-ca0d-4686-a8e0-876f614911dd" xlink:href="wlkp-20211231.xsd#wlkp_CashDistributionTrancheTwoMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DistributionTypeDomain_2e082878-ed85-44c9-96ee-c8d1a421d491" xlink:to="loc_wlkp_CashDistributionTrancheTwoMember_6cb1678d-ca0d-4686-a8e0-876f614911dd" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_wlkp_CashDistributionTrancheThreeMember_84fc0c06-da92-4dc4-b542-3392f157349f" xlink:href="wlkp-20211231.xsd#wlkp_CashDistributionTrancheThreeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DistributionTypeDomain_2e082878-ed85-44c9-96ee-c8d1a421d491" xlink:to="loc_wlkp_CashDistributionTrancheThreeMember_84fc0c06-da92-4dc4-b542-3392f157349f" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncentiveDistributionMadeToManagingMemberOrGeneralPartnerAxis_1b494f24-d1e7-4903-9fc9-bdef34eefe21" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncentiveDistributionMadeToManagingMemberOrGeneralPartnerAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DistributionsMadeToLimitedPartnerTable_8edb3953-5c33-4d8b-92d8-d57e1f09c4db" xlink:to="loc_us-gaap_IncentiveDistributionMadeToManagingMemberOrGeneralPartnerAxis_1b494f24-d1e7-4903-9fc9-bdef34eefe21" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncentiveDistributionRecipientDomain_1b494f24-d1e7-4903-9fc9-bdef34eefe21_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncentiveDistributionRecipientDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_IncentiveDistributionMadeToManagingMemberOrGeneralPartnerAxis_1b494f24-d1e7-4903-9fc9-bdef34eefe21" xlink:to="loc_us-gaap_IncentiveDistributionRecipientDomain_1b494f24-d1e7-4903-9fc9-bdef34eefe21_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncentiveDistributionRecipientDomain_9dff15fc-70c6-482b-892d-318478c7610a" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncentiveDistributionRecipientDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_IncentiveDistributionMadeToManagingMemberOrGeneralPartnerAxis_1b494f24-d1e7-4903-9fc9-bdef34eefe21" xlink:to="loc_us-gaap_IncentiveDistributionRecipientDomain_9dff15fc-70c6-482b-892d-318478c7610a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_wlkp_UnitHoldersMember_8a4e3767-b007-46cd-88a8-b1338afdf0db" xlink:href="wlkp-20211231.xsd#wlkp_UnitHoldersMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncentiveDistributionRecipientDomain_9dff15fc-70c6-482b-892d-318478c7610a" xlink:to="loc_wlkp_UnitHoldersMember_8a4e3767-b007-46cd-88a8-b1338afdf0db" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_wlkp_IDRHoldersMember_0baae7e3-7868-42c2-ae8c-57575a81f48b" xlink:href="wlkp-20211231.xsd#wlkp_IDRHoldersMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncentiveDistributionRecipientDomain_9dff15fc-70c6-482b-892d-318478c7610a" xlink:to="loc_wlkp_IDRHoldersMember_0baae7e3-7868-42c2-ae8c-57575a81f48b" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.westlake.com/role/DistributionsandNetIncomePerLimitedPartnerUnitIncomeInExcessOfDistributionDetails" xlink:type="simple" xlink:href="wlkp-20211231.xsd#DistributionsandNetIncomePerLimitedPartnerUnitIncomeInExcessOfDistributionDetails"/>
  <link:definitionLink xlink:role="http://www.westlake.com/role/DistributionsandNetIncomePerLimitedPartnerUnitIncomeInExcessOfDistributionDetails" xlink:type="extended" id="i63ed6f50bdf34f6c9ba867a4e73e10ec_DistributionsandNetIncomePerLimitedPartnerUnitIncomeInExcessOfDistributionDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems_02e59d5a-759b-49a1-b87e-20c071bbdd12" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StatementLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLoss_b1472985-ec2f-4852-8310-76219f865a08" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_NetIncomeLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_02e59d5a-759b-49a1-b87e-20c071bbdd12" xlink:to="loc_us-gaap_NetIncomeLoss_b1472985-ec2f-4852-8310-76219f865a08" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DistributedEarnings_b291e8bb-cee4-4ca8-b6b4-efcf5ab56e35" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DistributedEarnings"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_02e59d5a-759b-49a1-b87e-20c071bbdd12" xlink:to="loc_us-gaap_DistributedEarnings_b291e8bb-cee4-4ca8-b6b4-efcf5ab56e35" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_wlkp_IncentiveDistributionSubsequentDistributionAmount_b9cc32df-75a2-44ea-85ba-e0c6fa2d02e4" xlink:href="wlkp-20211231.xsd#wlkp_IncentiveDistributionSubsequentDistributionAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_02e59d5a-759b-49a1-b87e-20c071bbdd12" xlink:to="loc_wlkp_IncentiveDistributionSubsequentDistributionAmount_b9cc32df-75a2-44ea-85ba-e0c6fa2d02e4" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_UndistributedEarnings_e8ed81c3-840e-47c9-a4ec-b8e5ab4eac4b" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_UndistributedEarnings"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_02e59d5a-759b-49a1-b87e-20c071bbdd12" xlink:to="loc_us-gaap_UndistributedEarnings_e8ed81c3-840e-47c9-a4ec-b8e5ab4eac4b" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementTable_fd0967a7-7197-487c-af02-40130a13f527" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StatementTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_02e59d5a-759b-49a1-b87e-20c071bbdd12" xlink:to="loc_us-gaap_StatementTable_fd0967a7-7197-487c-af02-40130a13f527" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncentiveDistributionMadeToManagingMemberOrGeneralPartnerAxis_a434cee8-e6bd-4d1c-a166-49450edd0ff0" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncentiveDistributionMadeToManagingMemberOrGeneralPartnerAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_fd0967a7-7197-487c-af02-40130a13f527" xlink:to="loc_us-gaap_IncentiveDistributionMadeToManagingMemberOrGeneralPartnerAxis_a434cee8-e6bd-4d1c-a166-49450edd0ff0" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncentiveDistributionRecipientDomain_a434cee8-e6bd-4d1c-a166-49450edd0ff0_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncentiveDistributionRecipientDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_IncentiveDistributionMadeToManagingMemberOrGeneralPartnerAxis_a434cee8-e6bd-4d1c-a166-49450edd0ff0" xlink:to="loc_us-gaap_IncentiveDistributionRecipientDomain_a434cee8-e6bd-4d1c-a166-49450edd0ff0_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncentiveDistributionRecipientDomain_353176de-75ce-45eb-8446-94a3521e18c8" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncentiveDistributionRecipientDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_IncentiveDistributionMadeToManagingMemberOrGeneralPartnerAxis_a434cee8-e6bd-4d1c-a166-49450edd0ff0" xlink:to="loc_us-gaap_IncentiveDistributionRecipientDomain_353176de-75ce-45eb-8446-94a3521e18c8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_wlkp_IDRHoldersMember_275a5566-3c30-45a8-973d-1e40c45abc9b" xlink:href="wlkp-20211231.xsd#wlkp_IDRHoldersMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncentiveDistributionRecipientDomain_353176de-75ce-45eb-8446-94a3521e18c8" xlink:to="loc_wlkp_IDRHoldersMember_275a5566-3c30-45a8-973d-1e40c45abc9b" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LimitedPartnersCapitalAccountByClassAxis_efa71c8e-56e1-4161-82e3-9c311899eecc" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LimitedPartnersCapitalAccountByClassAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_fd0967a7-7197-487c-af02-40130a13f527" xlink:to="loc_us-gaap_LimitedPartnersCapitalAccountByClassAxis_efa71c8e-56e1-4161-82e3-9c311899eecc" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_efa71c8e-56e1-4161-82e3-9c311899eecc_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LimitedPartnersCapitalAccountClassDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountByClassAxis_efa71c8e-56e1-4161-82e3-9c311899eecc" xlink:to="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_efa71c8e-56e1-4161-82e3-9c311899eecc_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_16797a31-e116-45b2-b072-3702c926fb6f" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LimitedPartnersCapitalAccountClassDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountByClassAxis_efa71c8e-56e1-4161-82e3-9c311899eecc" xlink:to="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_16797a31-e116-45b2-b072-3702c926fb6f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_wlkp_CommonUnitsMember_c036bd12-8c19-4b50-b573-4f251186d27a" xlink:href="wlkp-20211231.xsd#wlkp_CommonUnitsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_16797a31-e116-45b2-b072-3702c926fb6f" xlink:to="loc_wlkp_CommonUnitsMember_c036bd12-8c19-4b50-b573-4f251186d27a" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.westlake.com/role/DistributionsandNetIncomePerLimitedPartnerUnitBasicandDilutedIncomePerLimitedPartnerUnitDetails" xlink:type="simple" xlink:href="wlkp-20211231.xsd#DistributionsandNetIncomePerLimitedPartnerUnitBasicandDilutedIncomePerLimitedPartnerUnitDetails"/>
  <link:definitionLink xlink:role="http://www.westlake.com/role/DistributionsandNetIncomePerLimitedPartnerUnitBasicandDilutedIncomePerLimitedPartnerUnitDetails" xlink:type="extended" id="icf460af1affb45d4b7a1c2e1989307b5_DistributionsandNetIncomePerLimitedPartnerUnitBasicandDilutedIncomePerLimitedPartnerUnitDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LimitedPartnersCapitalAccountLineItems_b4ee47e1-75ae-45f0-98f7-0f429b4c37b8" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LimitedPartnersCapitalAccountLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DistributedEarnings_1b5a79f1-b9f2-4d15-9f4a-ff6eba594bdf" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DistributedEarnings"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountLineItems_b4ee47e1-75ae-45f0-98f7-0f429b4c37b8" xlink:to="loc_us-gaap_DistributedEarnings_1b5a79f1-b9f2-4d15-9f4a-ff6eba594bdf" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_wlkp_IncentiveDistributionSubsequentDistributionAmount_bf111c6d-393d-49aa-a7bc-17a48e79079a" xlink:href="wlkp-20211231.xsd#wlkp_IncentiveDistributionSubsequentDistributionAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountLineItems_b4ee47e1-75ae-45f0-98f7-0f429b4c37b8" xlink:to="loc_wlkp_IncentiveDistributionSubsequentDistributionAmount_bf111c6d-393d-49aa-a7bc-17a48e79079a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_UndistributedEarnings_4fb4a1a6-da3f-410c-90b1-a163e0760b36" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_UndistributedEarnings"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountLineItems_b4ee47e1-75ae-45f0-98f7-0f429b4c37b8" xlink:to="loc_us-gaap_UndistributedEarnings_4fb4a1a6-da3f-410c-90b1-a163e0760b36" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLoss_a14c5aba-5ba0-43b3-9552-172a54ef42a4" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_NetIncomeLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountLineItems_b4ee47e1-75ae-45f0-98f7-0f429b4c37b8" xlink:to="loc_us-gaap_NetIncomeLoss_a14c5aba-5ba0-43b3-9552-172a54ef42a4" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EarningsPerShareBasicAndDilutedOtherDisclosuresAbstract_bfcc4c20-92eb-46c3-bd97-d21b93f13af5" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EarningsPerShareBasicAndDilutedOtherDisclosuresAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountLineItems_b4ee47e1-75ae-45f0-98f7-0f429b4c37b8" xlink:to="loc_us-gaap_EarningsPerShareBasicAndDilutedOtherDisclosuresAbstract_bfcc4c20-92eb-46c3-bd97-d21b93f13af5" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_WeightedAverageNumberOfShareOutstandingBasicAndDiluted_d0a8d962-30cb-44d2-8d58-41c4eb165ade" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_WeightedAverageNumberOfShareOutstandingBasicAndDiluted"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EarningsPerShareBasicAndDilutedOtherDisclosuresAbstract_bfcc4c20-92eb-46c3-bd97-d21b93f13af5" xlink:to="loc_us-gaap_WeightedAverageNumberOfShareOutstandingBasicAndDiluted_d0a8d962-30cb-44d2-8d58-41c4eb165ade" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLossPerOutstandingLimitedPartnershipUnitBasicNetOfTax_0e1640e5-9802-4598-9df8-faa15e53d8ef" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_NetIncomeLossPerOutstandingLimitedPartnershipUnitBasicNetOfTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountLineItems_b4ee47e1-75ae-45f0-98f7-0f429b4c37b8" xlink:to="loc_us-gaap_NetIncomeLossPerOutstandingLimitedPartnershipUnitBasicNetOfTax_0e1640e5-9802-4598-9df8-faa15e53d8ef" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfLimitedPartnersCapitalAccountByClassTable_1e3da84f-ee46-46cf-a14a-4f531776ec8b" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfLimitedPartnersCapitalAccountByClassTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountLineItems_b4ee47e1-75ae-45f0-98f7-0f429b4c37b8" xlink:to="loc_us-gaap_ScheduleOfLimitedPartnersCapitalAccountByClassTable_1e3da84f-ee46-46cf-a14a-4f531776ec8b" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LimitedPartnersCapitalAccountByClassAxis_ca839b72-8c41-4b6d-8b5d-19937b947e59" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LimitedPartnersCapitalAccountByClassAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfLimitedPartnersCapitalAccountByClassTable_1e3da84f-ee46-46cf-a14a-4f531776ec8b" xlink:to="loc_us-gaap_LimitedPartnersCapitalAccountByClassAxis_ca839b72-8c41-4b6d-8b5d-19937b947e59" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_ca839b72-8c41-4b6d-8b5d-19937b947e59_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LimitedPartnersCapitalAccountClassDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountByClassAxis_ca839b72-8c41-4b6d-8b5d-19937b947e59" xlink:to="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_ca839b72-8c41-4b6d-8b5d-19937b947e59_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_e314a8fb-c943-4982-b153-5742c2ed3939" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LimitedPartnersCapitalAccountClassDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountByClassAxis_ca839b72-8c41-4b6d-8b5d-19937b947e59" xlink:to="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_e314a8fb-c943-4982-b153-5742c2ed3939" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_wlkp_CommonUnitsMember_093787f3-fdb5-4e8e-9ade-e97c3c50716f" xlink:href="wlkp-20211231.xsd#wlkp_CommonUnitsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LimitedPartnersCapitalAccountClassDomain_e314a8fb-c943-4982-b153-5742c2ed3939" xlink:to="loc_wlkp_CommonUnitsMember_093787f3-fdb5-4e8e-9ade-e97c3c50716f" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncentiveDistributionMadeToManagingMemberOrGeneralPartnerAxis_7d60d7e3-19e8-4d1d-93d0-0fdeb980c6f3" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncentiveDistributionMadeToManagingMemberOrGeneralPartnerAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfLimitedPartnersCapitalAccountByClassTable_1e3da84f-ee46-46cf-a14a-4f531776ec8b" xlink:to="loc_us-gaap_IncentiveDistributionMadeToManagingMemberOrGeneralPartnerAxis_7d60d7e3-19e8-4d1d-93d0-0fdeb980c6f3" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncentiveDistributionRecipientDomain_7d60d7e3-19e8-4d1d-93d0-0fdeb980c6f3_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncentiveDistributionRecipientDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_IncentiveDistributionMadeToManagingMemberOrGeneralPartnerAxis_7d60d7e3-19e8-4d1d-93d0-0fdeb980c6f3" xlink:to="loc_us-gaap_IncentiveDistributionRecipientDomain_7d60d7e3-19e8-4d1d-93d0-0fdeb980c6f3_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncentiveDistributionRecipientDomain_2742ab9f-ce93-460d-8c90-996559c37116" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncentiveDistributionRecipientDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_IncentiveDistributionMadeToManagingMemberOrGeneralPartnerAxis_7d60d7e3-19e8-4d1d-93d0-0fdeb980c6f3" xlink:to="loc_us-gaap_IncentiveDistributionRecipientDomain_2742ab9f-ce93-460d-8c90-996559c37116" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_wlkp_IDRHoldersMember_fc898232-7347-4efa-852d-7a02f80a57da" xlink:href="wlkp-20211231.xsd#wlkp_IDRHoldersMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncentiveDistributionRecipientDomain_2742ab9f-ce93-460d-8c90-996559c37116" xlink:to="loc_wlkp_IDRHoldersMember_fc898232-7347-4efa-852d-7a02f80a57da" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DistributionsMadeToMemberOrLimitedPartnerByDistributionTypeAxis_4d8aedee-ec31-45bb-b1a2-aedff3772760" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DistributionsMadeToMemberOrLimitedPartnerByDistributionTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfLimitedPartnersCapitalAccountByClassTable_1e3da84f-ee46-46cf-a14a-4f531776ec8b" xlink:to="loc_us-gaap_DistributionsMadeToMemberOrLimitedPartnerByDistributionTypeAxis_4d8aedee-ec31-45bb-b1a2-aedff3772760" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DistributionTypeDomain_4d8aedee-ec31-45bb-b1a2-aedff3772760_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DistributionTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DistributionsMadeToMemberOrLimitedPartnerByDistributionTypeAxis_4d8aedee-ec31-45bb-b1a2-aedff3772760" xlink:to="loc_us-gaap_DistributionTypeDomain_4d8aedee-ec31-45bb-b1a2-aedff3772760_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DistributionTypeDomain_81d80f64-d523-4a4e-b67d-e55f18ffc303" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DistributionTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DistributionsMadeToMemberOrLimitedPartnerByDistributionTypeAxis_4d8aedee-ec31-45bb-b1a2-aedff3772760" xlink:to="loc_us-gaap_DistributionTypeDomain_81d80f64-d523-4a4e-b67d-e55f18ffc303" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashDistributionMember_580ba628-ff91-4cc3-8f52-2a87f6f793f7" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CashDistributionMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DistributionTypeDomain_81d80f64-d523-4a4e-b67d-e55f18ffc303" xlink:to="loc_us-gaap_CashDistributionMember_580ba628-ff91-4cc3-8f52-2a87f6f793f7" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.westlake.com/role/PartnersEquityIncentiveDistributionRightsDetails" xlink:type="simple" xlink:href="wlkp-20211231.xsd#PartnersEquityIncentiveDistributionRightsDetails"/>
  <link:definitionLink xlink:role="http://www.westlake.com/role/PartnersEquityIncentiveDistributionRightsDetails" xlink:type="extended" id="id41e2f73fa104bedac8a7c70b8457a18_PartnersEquityIncentiveDistributionRightsDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockLineItems_f4972fd9-0272-48d6-81ef-0135df8c75b4" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ClassOfStockLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_wlkp_PartnersUnitsMaximumAggregateOfferingAmountATM_9c488b60-f43c-4c08-9409-7a7af62757cb" xlink:href="wlkp-20211231.xsd#wlkp_PartnersUnitsMaximumAggregateOfferingAmountATM"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_f4972fd9-0272-48d6-81ef-0135df8c75b4" xlink:to="loc_wlkp_PartnersUnitsMaximumAggregateOfferingAmountATM_9c488b60-f43c-4c08-9409-7a7af62757cb" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PartnersCapitalAccountUnitsSoldInPublicOffering_61902710-7249-4d2a-a937-e6fec6945854" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PartnersCapitalAccountUnitsSoldInPublicOffering"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_f4972fd9-0272-48d6-81ef-0135df8c75b4" xlink:to="loc_us-gaap_PartnersCapitalAccountUnitsSoldInPublicOffering_61902710-7249-4d2a-a937-e6fec6945854" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_wlkp_PartnersCapitalAccountUnitsSoldinPublicOfferingPriceperUnit_68124bf5-8b30-4075-ba0b-f91ef0c06f16" xlink:href="wlkp-20211231.xsd#wlkp_PartnersCapitalAccountUnitsSoldinPublicOfferingPriceperUnit"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_f4972fd9-0272-48d6-81ef-0135df8c75b4" xlink:to="loc_wlkp_PartnersCapitalAccountUnitsSoldinPublicOfferingPriceperUnit_68124bf5-8b30-4075-ba0b-f91ef0c06f16" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_wlkp_PartnersCapitalAccountUnitsSoldtoRelatedParty_86d8fa6d-ebd7-4287-8f59-90154ed7d816" xlink:href="wlkp-20211231.xsd#wlkp_PartnersCapitalAccountUnitsSoldtoRelatedParty"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_f4972fd9-0272-48d6-81ef-0135df8c75b4" xlink:to="loc_wlkp_PartnersCapitalAccountUnitsSoldtoRelatedParty_86d8fa6d-ebd7-4287-8f59-90154ed7d816" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfStockByClassTable_253d2393-b009-4c9b-93e4-d6c690c88bb9" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfStockByClassTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ClassOfStockLineItems_f4972fd9-0272-48d6-81ef-0135df8c75b4" xlink:to="loc_us-gaap_ScheduleOfStockByClassTable_253d2393-b009-4c9b-93e4-d6c690c88bb9" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_6eead12f-b770-44f3-b8f3-093969014d37" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfStockByClassTable_253d2393-b009-4c9b-93e4-d6c690c88bb9" xlink:to="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_6eead12f-b770-44f3-b8f3-093969014d37" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_6eead12f-b770-44f3-b8f3-093969014d37_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_6eead12f-b770-44f3-b8f3-093969014d37" xlink:to="loc_us-gaap_RelatedPartyDomain_6eead12f-b770-44f3-b8f3-093969014d37_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_01cadcbe-c44b-442e-a372-7e8c9d3dd00f" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_6eead12f-b770-44f3-b8f3-093969014d37" xlink:to="loc_us-gaap_RelatedPartyDomain_01cadcbe-c44b-442e-a372-7e8c9d3dd00f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_AffiliatedEntityMember_3021344c-cb98-453a-9bd5-7c8f1dc10ab9" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_AffiliatedEntityMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyDomain_01cadcbe-c44b-442e-a372-7e8c9d3dd00f" xlink:to="loc_srt_AffiliatedEntityMember_3021344c-cb98-453a-9bd5-7c8f1dc10ab9" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PartnerTypeOfPartnersCapitalAccountAxis_6b453a0a-b565-4a4c-8ac3-8da33cabfe4a" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PartnerTypeOfPartnersCapitalAccountAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfStockByClassTable_253d2393-b009-4c9b-93e4-d6c690c88bb9" xlink:to="loc_us-gaap_PartnerTypeOfPartnersCapitalAccountAxis_6b453a0a-b565-4a4c-8ac3-8da33cabfe4a" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PartnerTypeOfPartnersCapitalAccountNameDomain_6b453a0a-b565-4a4c-8ac3-8da33cabfe4a_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PartnerTypeOfPartnersCapitalAccountNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_PartnerTypeOfPartnersCapitalAccountAxis_6b453a0a-b565-4a4c-8ac3-8da33cabfe4a" xlink:to="loc_us-gaap_PartnerTypeOfPartnersCapitalAccountNameDomain_6b453a0a-b565-4a4c-8ac3-8da33cabfe4a_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PartnerTypeOfPartnersCapitalAccountNameDomain_54d699b4-3abb-4f1a-a9dc-57ca8aa4f7a5" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PartnerTypeOfPartnersCapitalAccountNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_PartnerTypeOfPartnersCapitalAccountAxis_6b453a0a-b565-4a4c-8ac3-8da33cabfe4a" xlink:to="loc_us-gaap_PartnerTypeOfPartnersCapitalAccountNameDomain_54d699b4-3abb-4f1a-a9dc-57ca8aa4f7a5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LimitedPartnerMember_de018c69-6e95-4868-8022-cb34ecc34f6b" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LimitedPartnerMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PartnerTypeOfPartnersCapitalAccountNameDomain_54d699b4-3abb-4f1a-a9dc-57ca8aa4f7a5" xlink:to="loc_us-gaap_LimitedPartnerMember_de018c69-6e95-4868-8022-cb34ecc34f6b" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.westlake.com/role/RelatedPartyTransactionsCostofSalesfromRelatedPartiesDetails" xlink:type="simple" xlink:href="wlkp-20211231.xsd#RelatedPartyTransactionsCostofSalesfromRelatedPartiesDetails"/>
  <link:definitionLink xlink:role="http://www.westlake.com/role/RelatedPartyTransactionsCostofSalesfromRelatedPartiesDetails" xlink:type="extended" id="i0ee91d92b2c54e00a3aa1ac7c050c466_RelatedPartyTransactionsCostofSalesfromRelatedPartiesDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionLineItems_a4bfe383-1169-45f8-957c-40fc2bd3cf55" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RelatedPartyTransactionLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_wlkp_RelatedPartiesAmountInCostOfSalesFeedstockPurchased_e3bdb44f-1bb1-424d-b9a5-c2da88d1763f" xlink:href="wlkp-20211231.xsd#wlkp_RelatedPartiesAmountInCostOfSalesFeedstockPurchased"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_a4bfe383-1169-45f8-957c-40fc2bd3cf55" xlink:to="loc_wlkp_RelatedPartiesAmountInCostOfSalesFeedstockPurchased_e3bdb44f-1bb1-424d-b9a5-c2da88d1763f" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_wlkp_CostOfGoodsSoldOther_49571ecf-3a68-40a7-862e-aea7284cc8b9" xlink:href="wlkp-20211231.xsd#wlkp_CostOfGoodsSoldOther"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_a4bfe383-1169-45f8-957c-40fc2bd3cf55" xlink:to="loc_wlkp_CostOfGoodsSoldOther_49571ecf-3a68-40a7-862e-aea7284cc8b9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartiesAmountInCostOfSales_2b07354e-975d-4679-842e-7abd8e1b8281" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RelatedPartiesAmountInCostOfSales"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_a4bfe383-1169-45f8-957c-40fc2bd3cf55" xlink:to="loc_us-gaap_RelatedPartiesAmountInCostOfSales_2b07354e-975d-4679-842e-7abd8e1b8281" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_e6084382-dc44-49c0-94db-f0d7b8798255" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_a4bfe383-1169-45f8-957c-40fc2bd3cf55" xlink:to="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_e6084382-dc44-49c0-94db-f0d7b8798255" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_b31d9620-4a9f-469c-ad17-ad0f40c5784a" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_e6084382-dc44-49c0-94db-f0d7b8798255" xlink:to="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_b31d9620-4a9f-469c-ad17-ad0f40c5784a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_b31d9620-4a9f-469c-ad17-ad0f40c5784a_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_b31d9620-4a9f-469c-ad17-ad0f40c5784a" xlink:to="loc_us-gaap_RelatedPartyDomain_b31d9620-4a9f-469c-ad17-ad0f40c5784a_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_6ddd2ea5-1f77-4b8a-b9da-4302a481399d" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_b31d9620-4a9f-469c-ad17-ad0f40c5784a" xlink:to="loc_us-gaap_RelatedPartyDomain_6ddd2ea5-1f77-4b8a-b9da-4302a481399d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_AffiliatedEntityMember_14f56cae-28a9-4a88-bb2f-dbfb6164f6ef" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_AffiliatedEntityMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyDomain_6ddd2ea5-1f77-4b8a-b9da-4302a481399d" xlink:to="loc_srt_AffiliatedEntityMember_14f56cae-28a9-4a88-bb2f-dbfb6164f6ef" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CounterpartyNameAxis_f55840f4-008b-4527-ad9b-9a45b2707314" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_CounterpartyNameAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_e6084382-dc44-49c0-94db-f0d7b8798255" xlink:to="loc_srt_CounterpartyNameAxis_f55840f4-008b-4527-ad9b-9a45b2707314" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RepurchaseAgreementCounterpartyNameDomain_f55840f4-008b-4527-ad9b-9a45b2707314_default" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RepurchaseAgreementCounterpartyNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_CounterpartyNameAxis_f55840f4-008b-4527-ad9b-9a45b2707314" xlink:to="loc_srt_RepurchaseAgreementCounterpartyNameDomain_f55840f4-008b-4527-ad9b-9a45b2707314_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RepurchaseAgreementCounterpartyNameDomain_3e6eb288-fb72-4757-bb4d-67636357230f" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RepurchaseAgreementCounterpartyNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_CounterpartyNameAxis_f55840f4-008b-4527-ad9b-9a45b2707314" xlink:to="loc_srt_RepurchaseAgreementCounterpartyNameDomain_3e6eb288-fb72-4757-bb4d-67636357230f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember_9304e411-0fc4-4005-9ee2-ccf20ac14614" xlink:href="wlkp-20211231.xsd#wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RepurchaseAgreementCounterpartyNameDomain_3e6eb288-fb72-4757-bb4d-67636357230f" xlink:to="loc_wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember_9304e411-0fc4-4005-9ee2-ccf20ac14614" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.westlake.com/role/RelatedPartyTransactionsServicesfromRelatedPartiesIncludedinSGAExpensesDetails" xlink:type="simple" xlink:href="wlkp-20211231.xsd#RelatedPartyTransactionsServicesfromRelatedPartiesIncludedinSGAExpensesDetails"/>
  <link:definitionLink xlink:role="http://www.westlake.com/role/RelatedPartyTransactionsServicesfromRelatedPartiesIncludedinSGAExpensesDetails" xlink:type="extended" id="i0ae31104c7b54e2c972296e66dc091f2_RelatedPartyTransactionsServicesfromRelatedPartiesIncludedinSGAExpensesDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionLineItems_b4009bb5-1a8f-44e1-bb59-734193a58fe5" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RelatedPartyTransactionLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SellingGeneralAndAdministrativeExpense_fec0e895-3f06-4b28-80c8-20a63e782949" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SellingGeneralAndAdministrativeExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_b4009bb5-1a8f-44e1-bb59-734193a58fe5" xlink:to="loc_us-gaap_SellingGeneralAndAdministrativeExpense_fec0e895-3f06-4b28-80c8-20a63e782949" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_7f4f4494-78cd-4816-8208-a86cf0eb88b0" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_b4009bb5-1a8f-44e1-bb59-734193a58fe5" xlink:to="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_7f4f4494-78cd-4816-8208-a86cf0eb88b0" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_cc8a33c6-ebad-4d65-819b-12790e144041" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_7f4f4494-78cd-4816-8208-a86cf0eb88b0" xlink:to="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_cc8a33c6-ebad-4d65-819b-12790e144041" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_cc8a33c6-ebad-4d65-819b-12790e144041_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_cc8a33c6-ebad-4d65-819b-12790e144041" xlink:to="loc_us-gaap_RelatedPartyDomain_cc8a33c6-ebad-4d65-819b-12790e144041_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_94b5bac0-0ff0-42b2-9665-d8cea4677ebc" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_cc8a33c6-ebad-4d65-819b-12790e144041" xlink:to="loc_us-gaap_RelatedPartyDomain_94b5bac0-0ff0-42b2-9665-d8cea4677ebc" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_AffiliatedEntityMember_6ba06e85-c3f1-471f-a997-7fadf3ef70a3" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_AffiliatedEntityMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyDomain_94b5bac0-0ff0-42b2-9665-d8cea4677ebc" xlink:to="loc_srt_AffiliatedEntityMember_6ba06e85-c3f1-471f-a997-7fadf3ef70a3" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CounterpartyNameAxis_07a37612-5c07-46b5-b904-ae572453736f" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_CounterpartyNameAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_7f4f4494-78cd-4816-8208-a86cf0eb88b0" xlink:to="loc_srt_CounterpartyNameAxis_07a37612-5c07-46b5-b904-ae572453736f" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RepurchaseAgreementCounterpartyNameDomain_07a37612-5c07-46b5-b904-ae572453736f_default" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RepurchaseAgreementCounterpartyNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_CounterpartyNameAxis_07a37612-5c07-46b5-b904-ae572453736f" xlink:to="loc_srt_RepurchaseAgreementCounterpartyNameDomain_07a37612-5c07-46b5-b904-ae572453736f_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RepurchaseAgreementCounterpartyNameDomain_4052f8fb-29c0-42e9-85ba-4cc007e37e20" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RepurchaseAgreementCounterpartyNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_CounterpartyNameAxis_07a37612-5c07-46b5-b904-ae572453736f" xlink:to="loc_srt_RepurchaseAgreementCounterpartyNameDomain_4052f8fb-29c0-42e9-85ba-4cc007e37e20" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember_3ae572f6-5b11-4e76-90ab-c36000ceb735" xlink:href="wlkp-20211231.xsd#wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RepurchaseAgreementCounterpartyNameDomain_4052f8fb-29c0-42e9-85ba-4cc007e37e20" xlink:to="loc_wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember_3ae572f6-5b11-4e76-90ab-c36000ceb735" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.westlake.com/role/RelatedPartyTransactionsGoodsandServicesfromRelatedPartiesthathavebeenCapitalizedDetails" xlink:type="simple" xlink:href="wlkp-20211231.xsd#RelatedPartyTransactionsGoodsandServicesfromRelatedPartiesthathavebeenCapitalizedDetails"/>
  <link:definitionLink xlink:role="http://www.westlake.com/role/RelatedPartyTransactionsGoodsandServicesfromRelatedPartiesthathavebeenCapitalizedDetails" xlink:type="extended" id="i50680e1686314377a4027a064b239a33_RelatedPartyTransactionsGoodsandServicesfromRelatedPartiesthathavebeenCapitalizedDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionLineItems_69c8844e-d5b1-4fb6-9e65-762762e990c0" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RelatedPartyTransactionLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_wlkp_RelatedPartyTransactionPurchasesFromRelatedPartyCapitalizedAsAssets_b3e3365e-55de-45c5-9574-c3877109a90a" xlink:href="wlkp-20211231.xsd#wlkp_RelatedPartyTransactionPurchasesFromRelatedPartyCapitalizedAsAssets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_69c8844e-d5b1-4fb6-9e65-762762e990c0" xlink:to="loc_wlkp_RelatedPartyTransactionPurchasesFromRelatedPartyCapitalizedAsAssets_b3e3365e-55de-45c5-9574-c3877109a90a" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_6b1aeed5-b6e1-4054-a99e-bd16b92a9e49" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_69c8844e-d5b1-4fb6-9e65-762762e990c0" xlink:to="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_6b1aeed5-b6e1-4054-a99e-bd16b92a9e49" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_5cdec82a-611c-461d-ad71-30488c2660af" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_6b1aeed5-b6e1-4054-a99e-bd16b92a9e49" xlink:to="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_5cdec82a-611c-461d-ad71-30488c2660af" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_5cdec82a-611c-461d-ad71-30488c2660af_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_5cdec82a-611c-461d-ad71-30488c2660af" xlink:to="loc_us-gaap_RelatedPartyDomain_5cdec82a-611c-461d-ad71-30488c2660af_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_cb08dd84-f753-46ad-8f47-e88a3ad8f2f4" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_5cdec82a-611c-461d-ad71-30488c2660af" xlink:to="loc_us-gaap_RelatedPartyDomain_cb08dd84-f753-46ad-8f47-e88a3ad8f2f4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_AffiliatedEntityMember_f0250f16-ccab-4939-8f3e-9c7996f166c7" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_AffiliatedEntityMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyDomain_cb08dd84-f753-46ad-8f47-e88a3ad8f2f4" xlink:to="loc_srt_AffiliatedEntityMember_f0250f16-ccab-4939-8f3e-9c7996f166c7" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CounterpartyNameAxis_b6365565-ae0c-4c37-aea6-bbf4c50b2e2a" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_CounterpartyNameAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_6b1aeed5-b6e1-4054-a99e-bd16b92a9e49" xlink:to="loc_srt_CounterpartyNameAxis_b6365565-ae0c-4c37-aea6-bbf4c50b2e2a" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RepurchaseAgreementCounterpartyNameDomain_b6365565-ae0c-4c37-aea6-bbf4c50b2e2a_default" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RepurchaseAgreementCounterpartyNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_CounterpartyNameAxis_b6365565-ae0c-4c37-aea6-bbf4c50b2e2a" xlink:to="loc_srt_RepurchaseAgreementCounterpartyNameDomain_b6365565-ae0c-4c37-aea6-bbf4c50b2e2a_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RepurchaseAgreementCounterpartyNameDomain_3e87629c-1d24-4cba-ad7a-d38453676ad9" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RepurchaseAgreementCounterpartyNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_CounterpartyNameAxis_b6365565-ae0c-4c37-aea6-bbf4c50b2e2a" xlink:to="loc_srt_RepurchaseAgreementCounterpartyNameDomain_3e87629c-1d24-4cba-ad7a-d38453676ad9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember_c6a1435f-a697-4409-b781-cdd13df0528c" xlink:href="wlkp-20211231.xsd#wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RepurchaseAgreementCounterpartyNameDomain_3e87629c-1d24-4cba-ad7a-d38453676ad9" xlink:to="loc_wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember_c6a1435f-a697-4409-b781-cdd13df0528c" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.westlake.com/role/RelatedPartyTransactionsRelatedPartyTransactionsReceivableundertheInvestmentManagementAgreementDetails" xlink:type="simple" xlink:href="wlkp-20211231.xsd#RelatedPartyTransactionsRelatedPartyTransactionsReceivableundertheInvestmentManagementAgreementDetails"/>
  <link:definitionLink xlink:role="http://www.westlake.com/role/RelatedPartyTransactionsRelatedPartyTransactionsReceivableundertheInvestmentManagementAgreementDetails" xlink:type="extended" id="i70434cfba33e4d808a4063bd72dc5795_RelatedPartyTransactionsRelatedPartyTransactionsReceivableundertheInvestmentManagementAgreementDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionLineItems_a242b570-3e69-4688-a187-f979a3c076f3" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RelatedPartyTransactionLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_wlkp_AccruedinterestincludedinreceivableunderIMA_b25e6b6b-19fa-45e4-ae39-5853b52b4598" xlink:href="wlkp-20211231.xsd#wlkp_AccruedinterestincludedinreceivableunderIMA"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_a242b570-3e69-4688-a187-f979a3c076f3" xlink:to="loc_wlkp_AccruedinterestincludedinreceivableunderIMA_b25e6b6b-19fa-45e4-ae39-5853b52b4598" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_wlkp_InterestearnedrelatedtotheIMA_932e871e-ee16-4e75-88df-ac922b8fc920" xlink:href="wlkp-20211231.xsd#wlkp_InterestearnedrelatedtotheIMA"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_a242b570-3e69-4688-a187-f979a3c076f3" xlink:to="loc_wlkp_InterestearnedrelatedtotheIMA_932e871e-ee16-4e75-88df-ac922b8fc920" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_wlkp_IMAPartnershipEarnedAmountAddedToMarketRateBasisPoints_81ef33a5-d776-4f79-9ed5-374041bff3a3" xlink:href="wlkp-20211231.xsd#wlkp_IMAPartnershipEarnedAmountAddedToMarketRateBasisPoints"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_a242b570-3e69-4688-a187-f979a3c076f3" xlink:to="loc_wlkp_IMAPartnershipEarnedAmountAddedToMarketRateBasisPoints_81ef33a5-d776-4f79-9ed5-374041bff3a3" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_00e4be14-4e80-4079-b361-17fc83ef4932" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_a242b570-3e69-4688-a187-f979a3c076f3" xlink:to="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_00e4be14-4e80-4079-b361-17fc83ef4932" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CounterpartyNameAxis_3f629b65-9852-44cd-a88e-6964518d1aa1" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_CounterpartyNameAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_00e4be14-4e80-4079-b361-17fc83ef4932" xlink:to="loc_srt_CounterpartyNameAxis_3f629b65-9852-44cd-a88e-6964518d1aa1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RepurchaseAgreementCounterpartyNameDomain_3f629b65-9852-44cd-a88e-6964518d1aa1_default" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RepurchaseAgreementCounterpartyNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_CounterpartyNameAxis_3f629b65-9852-44cd-a88e-6964518d1aa1" xlink:to="loc_srt_RepurchaseAgreementCounterpartyNameDomain_3f629b65-9852-44cd-a88e-6964518d1aa1_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RepurchaseAgreementCounterpartyNameDomain_aaff44d7-8f4d-44e9-a858-c0a78fa238d4" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RepurchaseAgreementCounterpartyNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_CounterpartyNameAxis_3f629b65-9852-44cd-a88e-6964518d1aa1" xlink:to="loc_srt_RepurchaseAgreementCounterpartyNameDomain_aaff44d7-8f4d-44e9-a858-c0a78fa238d4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember_1fd76cf5-9d22-4ff6-929e-f745f6ce68c9" xlink:href="wlkp-20211231.xsd#wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RepurchaseAgreementCounterpartyNameDomain_aaff44d7-8f4d-44e9-a858-c0a78fa238d4" xlink:to="loc_wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember_1fd76cf5-9d22-4ff6-929e-f745f6ce68c9" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BalanceSheetLocationAxis_adf07119-cacb-4bed-afef-42979c0461ca" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BalanceSheetLocationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_00e4be14-4e80-4079-b361-17fc83ef4932" xlink:to="loc_us-gaap_BalanceSheetLocationAxis_adf07119-cacb-4bed-afef-42979c0461ca" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BalanceSheetLocationDomain_adf07119-cacb-4bed-afef-42979c0461ca_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BalanceSheetLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BalanceSheetLocationAxis_adf07119-cacb-4bed-afef-42979c0461ca" xlink:to="loc_us-gaap_BalanceSheetLocationDomain_adf07119-cacb-4bed-afef-42979c0461ca_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BalanceSheetLocationDomain_c09bad6f-ae54-41f0-a0cf-5e942f1c185f" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BalanceSheetLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BalanceSheetLocationAxis_adf07119-cacb-4bed-afef-42979c0461ca" xlink:to="loc_us-gaap_BalanceSheetLocationDomain_c09bad6f-ae54-41f0-a0cf-5e942f1c185f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccruedLiabilitiesMember_ebe24e4c-338d-4ac7-89b4-afa7c871d5e9" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AccruedLiabilitiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BalanceSheetLocationDomain_c09bad6f-ae54-41f0-a0cf-5e942f1c185f" xlink:to="loc_us-gaap_AccruedLiabilitiesMember_ebe24e4c-338d-4ac7-89b4-afa7c871d5e9" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_aa010d63-8b50-4d21-8aa6-ec2fbb67e7d4" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_00e4be14-4e80-4079-b361-17fc83ef4932" xlink:to="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_aa010d63-8b50-4d21-8aa6-ec2fbb67e7d4" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_aa010d63-8b50-4d21-8aa6-ec2fbb67e7d4_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_aa010d63-8b50-4d21-8aa6-ec2fbb67e7d4" xlink:to="loc_us-gaap_RelatedPartyDomain_aa010d63-8b50-4d21-8aa6-ec2fbb67e7d4_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_eb035c9c-9a8b-4412-b2cf-387797356109" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_aa010d63-8b50-4d21-8aa6-ec2fbb67e7d4" xlink:to="loc_us-gaap_RelatedPartyDomain_eb035c9c-9a8b-4412-b2cf-387797356109" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_AffiliatedEntityMember_a032c85b-1491-4d23-923b-e5068ec7285d" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_AffiliatedEntityMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyDomain_eb035c9c-9a8b-4412-b2cf-387797356109" xlink:to="loc_srt_AffiliatedEntityMember_a032c85b-1491-4d23-923b-e5068ec7285d" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.westlake.com/role/RelatedPartyTransactionsAccountsReceivablefromandAccountsPayabletoRelatedPartiesDetails" xlink:type="simple" xlink:href="wlkp-20211231.xsd#RelatedPartyTransactionsAccountsReceivablefromandAccountsPayabletoRelatedPartiesDetails"/>
  <link:definitionLink xlink:role="http://www.westlake.com/role/RelatedPartyTransactionsAccountsReceivablefromandAccountsPayabletoRelatedPartiesDetails" xlink:type="extended" id="i796c23ff31c84d748d434ac4fe5db91a_RelatedPartyTransactionsAccountsReceivablefromandAccountsPayabletoRelatedPartiesDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionLineItems_190012a7-660c-4dec-925d-7ab76fdeb0ba" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RelatedPartyTransactionLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_wlkp_LongtermPurchaseCommitmentMinimumPercentageRequired_8f951fba-437f-4686-ab56-5771f0c3243f" xlink:href="wlkp-20211231.xsd#wlkp_LongtermPurchaseCommitmentMinimumPercentageRequired"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_190012a7-660c-4dec-925d-7ab76fdeb0ba" xlink:to="loc_wlkp_LongtermPurchaseCommitmentMinimumPercentageRequired_8f951fba-437f-4686-ab56-5771f0c3243f" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountsReceivableRelatedPartiesCurrent_206665a3-f004-4186-a1cd-faf0dc6e628f" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AccountsReceivableRelatedPartiesCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_190012a7-660c-4dec-925d-7ab76fdeb0ba" xlink:to="loc_us-gaap_AccountsReceivableRelatedPartiesCurrent_206665a3-f004-4186-a1cd-faf0dc6e628f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountsPayableRelatedPartiesCurrent_e3c0559f-15b4-4a71-86fa-7968c419b4c5" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AccountsPayableRelatedPartiesCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_190012a7-660c-4dec-925d-7ab76fdeb0ba" xlink:to="loc_us-gaap_AccountsPayableRelatedPartiesCurrent_e3c0559f-15b4-4a71-86fa-7968c419b4c5" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_e69a92de-ccf6-4167-aee1-419753edc548" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_190012a7-660c-4dec-925d-7ab76fdeb0ba" xlink:to="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_e69a92de-ccf6-4167-aee1-419753edc548" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionAxis_260130a9-8089-4357-8c0a-e27df8e82548" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RelatedPartyTransactionAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_e69a92de-ccf6-4167-aee1-419753edc548" xlink:to="loc_us-gaap_RelatedPartyTransactionAxis_260130a9-8089-4357-8c0a-e27df8e82548" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionDomain_260130a9-8089-4357-8c0a-e27df8e82548_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RelatedPartyTransactionDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RelatedPartyTransactionAxis_260130a9-8089-4357-8c0a-e27df8e82548" xlink:to="loc_us-gaap_RelatedPartyTransactionDomain_260130a9-8089-4357-8c0a-e27df8e82548_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionDomain_14f12e20-8acf-4457-807c-cb0d8701673c" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RelatedPartyTransactionDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RelatedPartyTransactionAxis_260130a9-8089-4357-8c0a-e27df8e82548" xlink:to="loc_us-gaap_RelatedPartyTransactionDomain_14f12e20-8acf-4457-807c-cb0d8701673c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_wlkp_EthyleneSalesAgreementMember_90981810-a04b-4ed2-85eb-4b683b3da614" xlink:href="wlkp-20211231.xsd#wlkp_EthyleneSalesAgreementMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionDomain_14f12e20-8acf-4457-807c-cb0d8701673c" xlink:to="loc_wlkp_EthyleneSalesAgreementMember_90981810-a04b-4ed2-85eb-4b683b3da614" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_013acca8-dbdf-458c-8ca1-94a1894d50ac" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_e69a92de-ccf6-4167-aee1-419753edc548" xlink:to="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_013acca8-dbdf-458c-8ca1-94a1894d50ac" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_013acca8-dbdf-458c-8ca1-94a1894d50ac_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_013acca8-dbdf-458c-8ca1-94a1894d50ac" xlink:to="loc_us-gaap_RelatedPartyDomain_013acca8-dbdf-458c-8ca1-94a1894d50ac_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_3c0657f6-b90a-4d5a-abf2-0228d5b8c6e4" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_013acca8-dbdf-458c-8ca1-94a1894d50ac" xlink:to="loc_us-gaap_RelatedPartyDomain_3c0657f6-b90a-4d5a-abf2-0228d5b8c6e4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InvesteeMember_58931860-49b4-4ac4-a93e-2f80870d38fb" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_InvesteeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyDomain_3c0657f6-b90a-4d5a-abf2-0228d5b8c6e4" xlink:to="loc_us-gaap_InvesteeMember_58931860-49b4-4ac4-a93e-2f80870d38fb" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_AffiliatedEntityMember_cfc22949-b428-4171-9a1b-2ee11cec24cd" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_AffiliatedEntityMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyDomain_3c0657f6-b90a-4d5a-abf2-0228d5b8c6e4" xlink:to="loc_srt_AffiliatedEntityMember_cfc22949-b428-4171-9a1b-2ee11cec24cd" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CounterpartyNameAxis_fd8bcb8e-0646-45d1-ae17-599344ea7d14" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_CounterpartyNameAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_e69a92de-ccf6-4167-aee1-419753edc548" xlink:to="loc_srt_CounterpartyNameAxis_fd8bcb8e-0646-45d1-ae17-599344ea7d14" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RepurchaseAgreementCounterpartyNameDomain_fd8bcb8e-0646-45d1-ae17-599344ea7d14_default" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RepurchaseAgreementCounterpartyNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_CounterpartyNameAxis_fd8bcb8e-0646-45d1-ae17-599344ea7d14" xlink:to="loc_srt_RepurchaseAgreementCounterpartyNameDomain_fd8bcb8e-0646-45d1-ae17-599344ea7d14_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RepurchaseAgreementCounterpartyNameDomain_2986a3c7-1767-4f92-b53b-fe49ecd7f62c" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RepurchaseAgreementCounterpartyNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_CounterpartyNameAxis_fd8bcb8e-0646-45d1-ae17-599344ea7d14" xlink:to="loc_srt_RepurchaseAgreementCounterpartyNameDomain_2986a3c7-1767-4f92-b53b-fe49ecd7f62c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_wlkp_WestlakeChemicalOpCoLPMember_4816fb3d-720a-47dd-b362-4ad65eb3558d" xlink:href="wlkp-20211231.xsd#wlkp_WestlakeChemicalOpCoLPMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RepurchaseAgreementCounterpartyNameDomain_2986a3c7-1767-4f92-b53b-fe49ecd7f62c" xlink:to="loc_wlkp_WestlakeChemicalOpCoLPMember_4816fb3d-720a-47dd-b362-4ad65eb3558d" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember_566351c7-828b-4a79-b5bc-c1a8e5277824" xlink:href="wlkp-20211231.xsd#wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RepurchaseAgreementCounterpartyNameDomain_2986a3c7-1767-4f92-b53b-fe49ecd7f62c" xlink:to="loc_wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember_566351c7-828b-4a79-b5bc-c1a8e5277824" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.westlake.com/role/RelatedPartyTransactionsDebtPayabletoRelatedPartiesDetails" xlink:type="simple" xlink:href="wlkp-20211231.xsd#RelatedPartyTransactionsDebtPayabletoRelatedPartiesDetails"/>
  <link:definitionLink xlink:role="http://www.westlake.com/role/RelatedPartyTransactionsDebtPayabletoRelatedPartiesDetails" xlink:type="extended" id="ie41fe41257774ca191dd337a0a65aca3_RelatedPartyTransactionsDebtPayabletoRelatedPartiesDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionLineItems_da06e306-b073-4508-a5fe-80cd98b20ad5" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RelatedPartyTransactionLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestExpenseRelatedParty_12dc972b-2b9c-4f06-bfcf-fb0b5dab9579" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_InterestExpenseRelatedParty"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_da06e306-b073-4508-a5fe-80cd98b20ad5" xlink:to="loc_us-gaap_InterestExpenseRelatedParty_12dc972b-2b9c-4f06-bfcf-fb0b5dab9579" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestCostsCapitalized_c8ae7a7b-80b4-4e3e-a1f9-69531006164b" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_InterestCostsCapitalized"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_da06e306-b073-4508-a5fe-80cd98b20ad5" xlink:to="loc_us-gaap_InterestCostsCapitalized_c8ae7a7b-80b4-4e3e-a1f9-69531006164b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestPayableCurrent_4a9f7fa0-f7f0-4ec9-afd1-8531cad76237" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_InterestPayableCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_da06e306-b073-4508-a5fe-80cd98b20ad5" xlink:to="loc_us-gaap_InterestPayableCurrent_4a9f7fa0-f7f0-4ec9-afd1-8531cad76237" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DueToRelatedPartiesNoncurrent_01d5964f-a772-46f4-b41f-605fb393cb10" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DueToRelatedPartiesNoncurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_da06e306-b073-4508-a5fe-80cd98b20ad5" xlink:to="loc_us-gaap_DueToRelatedPartiesNoncurrent_01d5964f-a772-46f4-b41f-605fb393cb10" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_83b7dfab-1956-42e9-92f0-9b6ae4bc1d02" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_da06e306-b073-4508-a5fe-80cd98b20ad5" xlink:to="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_83b7dfab-1956-42e9-92f0-9b6ae4bc1d02" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BalanceSheetLocationAxis_f0847e8a-e05f-468c-a594-568bf28f495f" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BalanceSheetLocationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_83b7dfab-1956-42e9-92f0-9b6ae4bc1d02" xlink:to="loc_us-gaap_BalanceSheetLocationAxis_f0847e8a-e05f-468c-a594-568bf28f495f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BalanceSheetLocationDomain_f0847e8a-e05f-468c-a594-568bf28f495f_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BalanceSheetLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BalanceSheetLocationAxis_f0847e8a-e05f-468c-a594-568bf28f495f" xlink:to="loc_us-gaap_BalanceSheetLocationDomain_f0847e8a-e05f-468c-a594-568bf28f495f_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BalanceSheetLocationDomain_8d0ef1cb-244f-4aeb-a4ef-3e8f4ae01520" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BalanceSheetLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BalanceSheetLocationAxis_f0847e8a-e05f-468c-a594-568bf28f495f" xlink:to="loc_us-gaap_BalanceSheetLocationDomain_8d0ef1cb-244f-4aeb-a4ef-3e8f4ae01520" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccruedLiabilitiesMember_e1ed9f36-064d-45c4-9252-f4555646944e" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AccruedLiabilitiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BalanceSheetLocationDomain_8d0ef1cb-244f-4aeb-a4ef-3e8f4ae01520" xlink:to="loc_us-gaap_AccruedLiabilitiesMember_e1ed9f36-064d-45c4-9252-f4555646944e" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_28f088c5-a097-4e29-afc7-98d345840042" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_83b7dfab-1956-42e9-92f0-9b6ae4bc1d02" xlink:to="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_28f088c5-a097-4e29-afc7-98d345840042" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_28f088c5-a097-4e29-afc7-98d345840042_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_28f088c5-a097-4e29-afc7-98d345840042" xlink:to="loc_us-gaap_RelatedPartyDomain_28f088c5-a097-4e29-afc7-98d345840042_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_01dd4476-22e3-4767-92f5-360657b74631" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_28f088c5-a097-4e29-afc7-98d345840042" xlink:to="loc_us-gaap_RelatedPartyDomain_01dd4476-22e3-4767-92f5-360657b74631" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_AffiliatedEntityMember_3bc26dcd-5642-4999-be22-010dfcaace94" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_AffiliatedEntityMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyDomain_01dd4476-22e3-4767-92f5-360657b74631" xlink:to="loc_srt_AffiliatedEntityMember_3bc26dcd-5642-4999-be22-010dfcaace94" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CounterpartyNameAxis_6b009c92-90e8-4f24-acce-123cbda03b75" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_CounterpartyNameAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_83b7dfab-1956-42e9-92f0-9b6ae4bc1d02" xlink:to="loc_srt_CounterpartyNameAxis_6b009c92-90e8-4f24-acce-123cbda03b75" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RepurchaseAgreementCounterpartyNameDomain_6b009c92-90e8-4f24-acce-123cbda03b75_default" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RepurchaseAgreementCounterpartyNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_CounterpartyNameAxis_6b009c92-90e8-4f24-acce-123cbda03b75" xlink:to="loc_srt_RepurchaseAgreementCounterpartyNameDomain_6b009c92-90e8-4f24-acce-123cbda03b75_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RepurchaseAgreementCounterpartyNameDomain_b34008c3-ba9a-4815-9f03-9e4b65fa3369" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RepurchaseAgreementCounterpartyNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_CounterpartyNameAxis_6b009c92-90e8-4f24-acce-123cbda03b75" xlink:to="loc_srt_RepurchaseAgreementCounterpartyNameDomain_b34008c3-ba9a-4815-9f03-9e4b65fa3369" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember_1064b029-bca0-47ae-bbb4-20f34257a253" xlink:href="wlkp-20211231.xsd#wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RepurchaseAgreementCounterpartyNameDomain_b34008c3-ba9a-4815-9f03-9e4b65fa3369" xlink:to="loc_wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember_1064b029-bca0-47ae-bbb4-20f34257a253" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.westlake.com/role/RelatedPartyTransactionsGeneralDetails" xlink:type="simple" xlink:href="wlkp-20211231.xsd#RelatedPartyTransactionsGeneralDetails"/>
  <link:definitionLink xlink:role="http://www.westlake.com/role/RelatedPartyTransactionsGeneralDetails" xlink:type="extended" id="i2afd56143aff4e7ab3219ce02cbb781e_RelatedPartyTransactionsGeneralDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionLineItems_37de792c-9a94-441b-bb54-3cc08153f6a5" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RelatedPartyTransactionLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskPercentage1_dc3c7fe2-f3f0-4348-a432-afb554d58206" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ConcentrationRiskPercentage1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_37de792c-9a94-441b-bb54-3cc08153f6a5" xlink:to="loc_us-gaap_ConcentrationRiskPercentage1_dc3c7fe2-f3f0-4348-a432-afb554d58206" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxesPaid_d7d679ff-073f-4179-b902-9ab08e61899c" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncomeTaxesPaid"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_37de792c-9a94-441b-bb54-3cc08153f6a5" xlink:to="loc_us-gaap_IncomeTaxesPaid_d7d679ff-073f-4179-b902-9ab08e61899c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeOperatingLeaseTermOfContract_f5434048-a4b5-491b-8097-ed6facc6405b" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LesseeOperatingLeaseTermOfContract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_37de792c-9a94-441b-bb54-3cc08153f6a5" xlink:to="loc_us-gaap_LesseeOperatingLeaseTermOfContract_f5434048-a4b5-491b-8097-ed6facc6405b" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_302d97b8-ec91-4e91-a4cd-049c6c1df46b" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_37de792c-9a94-441b-bb54-3cc08153f6a5" xlink:to="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_302d97b8-ec91-4e91-a4cd-049c6c1df46b" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_ce379ebc-acea-4890-8fbf-d9e17ac65482" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ConcentrationRiskByBenchmarkAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_302d97b8-ec91-4e91-a4cd-049c6c1df46b" xlink:to="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_ce379ebc-acea-4890-8fbf-d9e17ac65482" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskBenchmarkDomain_ce379ebc-acea-4890-8fbf-d9e17ac65482_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ConcentrationRiskBenchmarkDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_ce379ebc-acea-4890-8fbf-d9e17ac65482" xlink:to="loc_us-gaap_ConcentrationRiskBenchmarkDomain_ce379ebc-acea-4890-8fbf-d9e17ac65482_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskBenchmarkDomain_0243f46d-09b1-4f40-8331-cf376cdb083b" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ConcentrationRiskBenchmarkDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_ce379ebc-acea-4890-8fbf-d9e17ac65482" xlink:to="loc_us-gaap_ConcentrationRiskBenchmarkDomain_0243f46d-09b1-4f40-8331-cf376cdb083b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SalesRevenueNetMember_4602d288-2383-49ad-920b-12dc8bcc1904" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SalesRevenueNetMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConcentrationRiskBenchmarkDomain_0243f46d-09b1-4f40-8331-cf376cdb083b" xlink:to="loc_us-gaap_SalesRevenueNetMember_4602d288-2383-49ad-920b-12dc8bcc1904" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskByTypeAxis_4d427cad-cff3-4a83-9238-26fa1b3e8c3e" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ConcentrationRiskByTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_302d97b8-ec91-4e91-a4cd-049c6c1df46b" xlink:to="loc_us-gaap_ConcentrationRiskByTypeAxis_4d427cad-cff3-4a83-9238-26fa1b3e8c3e" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskTypeDomain_4d427cad-cff3-4a83-9238-26fa1b3e8c3e_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ConcentrationRiskTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ConcentrationRiskByTypeAxis_4d427cad-cff3-4a83-9238-26fa1b3e8c3e" xlink:to="loc_us-gaap_ConcentrationRiskTypeDomain_4d427cad-cff3-4a83-9238-26fa1b3e8c3e_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskTypeDomain_2bd9f7f2-69c4-4977-b492-021dc2a0820e" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ConcentrationRiskTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ConcentrationRiskByTypeAxis_4d427cad-cff3-4a83-9238-26fa1b3e8c3e" xlink:to="loc_us-gaap_ConcentrationRiskTypeDomain_2bd9f7f2-69c4-4977-b492-021dc2a0820e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CustomerConcentrationRiskMember_78c3ee46-c1d2-4295-8178-8d6b67d0f02d" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CustomerConcentrationRiskMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConcentrationRiskTypeDomain_2bd9f7f2-69c4-4977-b492-021dc2a0820e" xlink:to="loc_us-gaap_CustomerConcentrationRiskMember_78c3ee46-c1d2-4295-8178-8d6b67d0f02d" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MajorCustomersAxis_5f3096a9-0804-4ced-8283-bee18d2f6954" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_MajorCustomersAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_302d97b8-ec91-4e91-a4cd-049c6c1df46b" xlink:to="loc_srt_MajorCustomersAxis_5f3096a9-0804-4ced-8283-bee18d2f6954" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_NameOfMajorCustomerDomain_5f3096a9-0804-4ced-8283-bee18d2f6954_default" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_NameOfMajorCustomerDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_MajorCustomersAxis_5f3096a9-0804-4ced-8283-bee18d2f6954" xlink:to="loc_srt_NameOfMajorCustomerDomain_5f3096a9-0804-4ced-8283-bee18d2f6954_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_NameOfMajorCustomerDomain_1ec9e8fd-1d5c-4ff6-8e75-cdeec0af320c" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_NameOfMajorCustomerDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_MajorCustomersAxis_5f3096a9-0804-4ced-8283-bee18d2f6954" xlink:to="loc_srt_NameOfMajorCustomerDomain_1ec9e8fd-1d5c-4ff6-8e75-cdeec0af320c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember_5d397c70-ed6c-4283-a2f5-97b249dfc759" xlink:href="wlkp-20211231.xsd#wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_NameOfMajorCustomerDomain_1ec9e8fd-1d5c-4ff6-8e75-cdeec0af320c" xlink:to="loc_wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember_5d397c70-ed6c-4283-a2f5-97b249dfc759" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_63e0021d-5be5-4b47-8b84-842a568dd36b" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_302d97b8-ec91-4e91-a4cd-049c6c1df46b" xlink:to="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_63e0021d-5be5-4b47-8b84-842a568dd36b" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_63e0021d-5be5-4b47-8b84-842a568dd36b_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_63e0021d-5be5-4b47-8b84-842a568dd36b" xlink:to="loc_us-gaap_RelatedPartyDomain_63e0021d-5be5-4b47-8b84-842a568dd36b_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_efcb1c82-6976-488b-a318-77d0f5e5c16f" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_63e0021d-5be5-4b47-8b84-842a568dd36b" xlink:to="loc_us-gaap_RelatedPartyDomain_efcb1c82-6976-488b-a318-77d0f5e5c16f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_AffiliatedEntityMember_d5ecc32a-a66e-451d-abb3-f29f4e21d27b" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_AffiliatedEntityMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyDomain_efcb1c82-6976-488b-a318-77d0f5e5c16f" xlink:to="loc_srt_AffiliatedEntityMember_d5ecc32a-a66e-451d-abb3-f29f4e21d27b" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InvesteeMember_93695ef5-8aa0-4777-8cce-65a380536a5a" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_InvesteeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyDomain_efcb1c82-6976-488b-a318-77d0f5e5c16f" xlink:to="loc_us-gaap_InvesteeMember_93695ef5-8aa0-4777-8cce-65a380536a5a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_LegalEntityAxis_64f3534e-601e-4609-a859-bd3baf15cd6f" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_LegalEntityAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_302d97b8-ec91-4e91-a4cd-049c6c1df46b" xlink:to="loc_dei_LegalEntityAxis_64f3534e-601e-4609-a859-bd3baf15cd6f" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityDomain_64f3534e-601e-4609-a859-bd3baf15cd6f_default" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_EntityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_dei_LegalEntityAxis_64f3534e-601e-4609-a859-bd3baf15cd6f" xlink:to="loc_dei_EntityDomain_64f3534e-601e-4609-a859-bd3baf15cd6f_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityDomain_e087427f-45d0-4aa8-b95c-a4a9ef142925" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_EntityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_dei_LegalEntityAxis_64f3534e-601e-4609-a859-bd3baf15cd6f" xlink:to="loc_dei_EntityDomain_e087427f-45d0-4aa8-b95c-a4a9ef142925" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember_024bc9c9-3836-40ce-9b38-af79bbacbd85" xlink:href="wlkp-20211231.xsd#wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_e087427f-45d0-4aa8-b95c-a4a9ef142925" xlink:to="loc_wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember_024bc9c9-3836-40ce-9b38-af79bbacbd85" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionAxis_84905e5c-d393-4e33-b7fc-c6cdf33427cd" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RelatedPartyTransactionAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_302d97b8-ec91-4e91-a4cd-049c6c1df46b" xlink:to="loc_us-gaap_RelatedPartyTransactionAxis_84905e5c-d393-4e33-b7fc-c6cdf33427cd" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionDomain_84905e5c-d393-4e33-b7fc-c6cdf33427cd_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RelatedPartyTransactionDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RelatedPartyTransactionAxis_84905e5c-d393-4e33-b7fc-c6cdf33427cd" xlink:to="loc_us-gaap_RelatedPartyTransactionDomain_84905e5c-d393-4e33-b7fc-c6cdf33427cd_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionDomain_1179b120-d4e3-4599-b1c7-848eb5d35283" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RelatedPartyTransactionDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RelatedPartyTransactionAxis_84905e5c-d393-4e33-b7fc-c6cdf33427cd" xlink:to="loc_us-gaap_RelatedPartyTransactionDomain_1179b120-d4e3-4599-b1c7-848eb5d35283" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_wlkp_ReimbursementtoParentforStateTaxMember_8db6bc6d-8f61-4add-96a2-d30a8efbf7ab" xlink:href="wlkp-20211231.xsd#wlkp_ReimbursementtoParentforStateTaxMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionDomain_1179b120-d4e3-4599-b1c7-848eb5d35283" xlink:to="loc_wlkp_ReimbursementtoParentforStateTaxMember_8db6bc6d-8f61-4add-96a2-d30a8efbf7ab" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_wlkp_SiteLeaseAgreementMember_7e07e154-e4c0-4e0d-8f36-90caee627224" xlink:href="wlkp-20211231.xsd#wlkp_SiteLeaseAgreementMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionDomain_1179b120-d4e3-4599-b1c7-848eb5d35283" xlink:to="loc_wlkp_SiteLeaseAgreementMember_7e07e154-e4c0-4e0d-8f36-90caee627224" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CounterpartyNameAxis_41846caf-ea0e-4f6a-ac4a-9d362bb22923" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_CounterpartyNameAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_302d97b8-ec91-4e91-a4cd-049c6c1df46b" xlink:to="loc_srt_CounterpartyNameAxis_41846caf-ea0e-4f6a-ac4a-9d362bb22923" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RepurchaseAgreementCounterpartyNameDomain_41846caf-ea0e-4f6a-ac4a-9d362bb22923_default" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RepurchaseAgreementCounterpartyNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_CounterpartyNameAxis_41846caf-ea0e-4f6a-ac4a-9d362bb22923" xlink:to="loc_srt_RepurchaseAgreementCounterpartyNameDomain_41846caf-ea0e-4f6a-ac4a-9d362bb22923_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RepurchaseAgreementCounterpartyNameDomain_eaa141ef-0c92-42df-910f-b109a94867ca" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RepurchaseAgreementCounterpartyNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_CounterpartyNameAxis_41846caf-ea0e-4f6a-ac4a-9d362bb22923" xlink:to="loc_srt_RepurchaseAgreementCounterpartyNameDomain_eaa141ef-0c92-42df-910f-b109a94867ca" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember_d81780d0-70e8-42cc-b4fc-b250331e5cf3" xlink:href="wlkp-20211231.xsd#wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RepurchaseAgreementCounterpartyNameDomain_eaa141ef-0c92-42df-910f-b109a94867ca" xlink:to="loc_wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember_d81780d0-70e8-42cc-b4fc-b250331e5cf3" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_wlkp_WestlakeChemicalOpCoLPMember_d7d1ec1e-4934-4fcc-88fa-9089b76066be" xlink:href="wlkp-20211231.xsd#wlkp_WestlakeChemicalOpCoLPMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RepurchaseAgreementCounterpartyNameDomain_eaa141ef-0c92-42df-910f-b109a94867ca" xlink:to="loc_wlkp_WestlakeChemicalOpCoLPMember_d7d1ec1e-4934-4fcc-88fa-9089b76066be" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.westlake.com/role/RelatedPartyTransactionsRelatedPartyTransactionsRelatedPartyLeasesDetails" xlink:type="simple" xlink:href="wlkp-20211231.xsd#RelatedPartyTransactionsRelatedPartyTransactionsRelatedPartyLeasesDetails"/>
  <link:definitionLink xlink:role="http://www.westlake.com/role/RelatedPartyTransactionsRelatedPartyTransactionsRelatedPartyLeasesDetails" xlink:type="extended" id="i7f5bf07a3d924f0eb3aeb2ba38b294f3_RelatedPartyTransactionsRelatedPartyTransactionsRelatedPartyLeasesDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionLineItems_465dd0ed-de7d-4ccb-ae7f-3df96b3047c1" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RelatedPartyTransactionLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeaseExpense_9eff8a05-4ac4-4e96-aeb9-1eba8e40f65c" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OperatingLeaseExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_465dd0ed-de7d-4ccb-ae7f-3df96b3047c1" xlink:to="loc_us-gaap_OperatingLeaseExpense_9eff8a05-4ac4-4e96-aeb9-1eba8e40f65c" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_wlkp_Siteleaseagreementnumber_60d74b5d-5268-434f-9172-c920f7e6d133" xlink:href="wlkp-20211231.xsd#wlkp_Siteleaseagreementnumber"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_465dd0ed-de7d-4ccb-ae7f-3df96b3047c1" xlink:to="loc_wlkp_Siteleaseagreementnumber_60d74b5d-5268-434f-9172-c920f7e6d133" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeOperatingLeaseTermOfContract_5b5240fa-fbbb-4aba-95c6-0b16ea608c65" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LesseeOperatingLeaseTermOfContract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_465dd0ed-de7d-4ccb-ae7f-3df96b3047c1" xlink:to="loc_us-gaap_LesseeOperatingLeaseTermOfContract_5b5240fa-fbbb-4aba-95c6-0b16ea608c65" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_wlkp_Siteleaseexpense_2eb54d1c-3136-4e6c-8a80-c9ffe2028e3b" xlink:href="wlkp-20211231.xsd#wlkp_Siteleaseexpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_465dd0ed-de7d-4ccb-ae7f-3df96b3047c1" xlink:to="loc_wlkp_Siteleaseexpense_2eb54d1c-3136-4e6c-8a80-c9ffe2028e3b" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_69292e32-fba6-4483-9c50-fa27cedb2e09" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_465dd0ed-de7d-4ccb-ae7f-3df96b3047c1" xlink:to="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_69292e32-fba6-4483-9c50-fa27cedb2e09" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CounterpartyNameAxis_627f57e2-4930-44cd-a9c5-a4615dd8465a" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_CounterpartyNameAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_69292e32-fba6-4483-9c50-fa27cedb2e09" xlink:to="loc_srt_CounterpartyNameAxis_627f57e2-4930-44cd-a9c5-a4615dd8465a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RepurchaseAgreementCounterpartyNameDomain_627f57e2-4930-44cd-a9c5-a4615dd8465a_default" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RepurchaseAgreementCounterpartyNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_CounterpartyNameAxis_627f57e2-4930-44cd-a9c5-a4615dd8465a" xlink:to="loc_srt_RepurchaseAgreementCounterpartyNameDomain_627f57e2-4930-44cd-a9c5-a4615dd8465a_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RepurchaseAgreementCounterpartyNameDomain_45923842-a3ea-44bd-b4c8-be2bc098b115" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RepurchaseAgreementCounterpartyNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_CounterpartyNameAxis_627f57e2-4930-44cd-a9c5-a4615dd8465a" xlink:to="loc_srt_RepurchaseAgreementCounterpartyNameDomain_45923842-a3ea-44bd-b4c8-be2bc098b115" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_wlkp_WestlakeChemicalOpCoLPMember_6a2b172c-14a0-413e-bb73-7a77784ce0d6" xlink:href="wlkp-20211231.xsd#wlkp_WestlakeChemicalOpCoLPMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RepurchaseAgreementCounterpartyNameDomain_45923842-a3ea-44bd-b4c8-be2bc098b115" xlink:to="loc_wlkp_WestlakeChemicalOpCoLPMember_6a2b172c-14a0-413e-bb73-7a77784ce0d6" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember_8924b1e8-3cd3-4c87-80fc-5825e99be3d2" xlink:href="wlkp-20211231.xsd#wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RepurchaseAgreementCounterpartyNameDomain_45923842-a3ea-44bd-b4c8-be2bc098b115" xlink:to="loc_wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember_8924b1e8-3cd3-4c87-80fc-5825e99be3d2" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_LegalEntityAxis_a341b66c-995d-4b52-8ca2-69e7f84ce2ff" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_LegalEntityAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_69292e32-fba6-4483-9c50-fa27cedb2e09" xlink:to="loc_dei_LegalEntityAxis_a341b66c-995d-4b52-8ca2-69e7f84ce2ff" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityDomain_a341b66c-995d-4b52-8ca2-69e7f84ce2ff_default" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_EntityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_dei_LegalEntityAxis_a341b66c-995d-4b52-8ca2-69e7f84ce2ff" xlink:to="loc_dei_EntityDomain_a341b66c-995d-4b52-8ca2-69e7f84ce2ff_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityDomain_d3ef8da2-34c8-4511-925b-bd9c5822b05c" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_EntityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_dei_LegalEntityAxis_a341b66c-995d-4b52-8ca2-69e7f84ce2ff" xlink:to="loc_dei_EntityDomain_d3ef8da2-34c8-4511-925b-bd9c5822b05c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember_f44d387f-7dba-46fe-bc37-066d5cabdff5" xlink:href="wlkp-20211231.xsd#wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_d3ef8da2-34c8-4511-925b-bd9c5822b05c" xlink:to="loc_wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember_f44d387f-7dba-46fe-bc37-066d5cabdff5" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_027841c6-e9c2-4c07-9e6a-1d2cade63d46" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_69292e32-fba6-4483-9c50-fa27cedb2e09" xlink:to="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_027841c6-e9c2-4c07-9e6a-1d2cade63d46" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_027841c6-e9c2-4c07-9e6a-1d2cade63d46_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_027841c6-e9c2-4c07-9e6a-1d2cade63d46" xlink:to="loc_us-gaap_RelatedPartyDomain_027841c6-e9c2-4c07-9e6a-1d2cade63d46_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_fe8c0ff8-1093-4b6c-8383-0c1c22700de1" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_027841c6-e9c2-4c07-9e6a-1d2cade63d46" xlink:to="loc_us-gaap_RelatedPartyDomain_fe8c0ff8-1093-4b6c-8383-0c1c22700de1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InvesteeMember_2bbf9713-7c0a-4308-933f-2d209c353c21" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_InvesteeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyDomain_fe8c0ff8-1093-4b6c-8383-0c1c22700de1" xlink:to="loc_us-gaap_InvesteeMember_2bbf9713-7c0a-4308-933f-2d209c353c21" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_AffiliatedEntityMember_7ccc616e-f7a9-48d2-990a-0de2818813c0" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_AffiliatedEntityMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyDomain_fe8c0ff8-1093-4b6c-8383-0c1c22700de1" xlink:to="loc_srt_AffiliatedEntityMember_7ccc616e-f7a9-48d2-990a-0de2818813c0" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionAxis_c4c8fcef-87fb-4a92-8433-6326a0c949d2" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RelatedPartyTransactionAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_69292e32-fba6-4483-9c50-fa27cedb2e09" xlink:to="loc_us-gaap_RelatedPartyTransactionAxis_c4c8fcef-87fb-4a92-8433-6326a0c949d2" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionDomain_c4c8fcef-87fb-4a92-8433-6326a0c949d2_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RelatedPartyTransactionDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RelatedPartyTransactionAxis_c4c8fcef-87fb-4a92-8433-6326a0c949d2" xlink:to="loc_us-gaap_RelatedPartyTransactionDomain_c4c8fcef-87fb-4a92-8433-6326a0c949d2_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionDomain_90ce8abb-b5bd-4021-9d00-51ed0a643444" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RelatedPartyTransactionDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RelatedPartyTransactionAxis_c4c8fcef-87fb-4a92-8433-6326a0c949d2" xlink:to="loc_us-gaap_RelatedPartyTransactionDomain_90ce8abb-b5bd-4021-9d00-51ed0a643444" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_wlkp_SiteLeaseAgreementMember_d0859880-b2b3-4941-8177-ff228b4df4d5" xlink:href="wlkp-20211231.xsd#wlkp_SiteLeaseAgreementMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionDomain_90ce8abb-b5bd-4021-9d00-51ed0a643444" xlink:to="loc_wlkp_SiteLeaseAgreementMember_d0859880-b2b3-4941-8177-ff228b4df4d5" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.westlake.com/role/RelatedPartyTransactionsRelatedPartyTransactionsMajorCustomerandCreditRiskDetails" xlink:type="simple" xlink:href="wlkp-20211231.xsd#RelatedPartyTransactionsRelatedPartyTransactionsMajorCustomerandCreditRiskDetails"/>
  <link:definitionLink xlink:role="http://www.westlake.com/role/RelatedPartyTransactionsRelatedPartyTransactionsMajorCustomerandCreditRiskDetails" xlink:type="extended" id="i14e027bb0a2d4f7595bd2ab41167b6e5_RelatedPartyTransactionsRelatedPartyTransactionsMajorCustomerandCreditRiskDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionLineItems_a5894cd2-2d1f-41e1-b48c-b73652986c54" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RelatedPartyTransactionLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskPercentage1_963ae8c8-98c7-41a1-98c3-486d31bac848" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ConcentrationRiskPercentage1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_a5894cd2-2d1f-41e1-b48c-b73652986c54" xlink:to="loc_us-gaap_ConcentrationRiskPercentage1_963ae8c8-98c7-41a1-98c3-486d31bac848" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_df8a09fe-eea0-4eb9-af8d-777eda7e3243" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_a5894cd2-2d1f-41e1-b48c-b73652986c54" xlink:to="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_df8a09fe-eea0-4eb9-af8d-777eda7e3243" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_b90237c3-7d7c-489b-bd0d-4d32088a65ca" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ConcentrationRiskByBenchmarkAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_df8a09fe-eea0-4eb9-af8d-777eda7e3243" xlink:to="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_b90237c3-7d7c-489b-bd0d-4d32088a65ca" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskBenchmarkDomain_b90237c3-7d7c-489b-bd0d-4d32088a65ca_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ConcentrationRiskBenchmarkDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_b90237c3-7d7c-489b-bd0d-4d32088a65ca" xlink:to="loc_us-gaap_ConcentrationRiskBenchmarkDomain_b90237c3-7d7c-489b-bd0d-4d32088a65ca_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskBenchmarkDomain_f0b25d1d-c8ae-497d-8245-0ceefb67f587" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ConcentrationRiskBenchmarkDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_b90237c3-7d7c-489b-bd0d-4d32088a65ca" xlink:to="loc_us-gaap_ConcentrationRiskBenchmarkDomain_f0b25d1d-c8ae-497d-8245-0ceefb67f587" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SalesRevenueNetMember_098ded00-cacd-45d2-be37-19e55a4aa3c7" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SalesRevenueNetMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConcentrationRiskBenchmarkDomain_f0b25d1d-c8ae-497d-8245-0ceefb67f587" xlink:to="loc_us-gaap_SalesRevenueNetMember_098ded00-cacd-45d2-be37-19e55a4aa3c7" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MajorCustomersAxis_9317b9ad-ba81-4cb4-a2de-9e69ec8da41b" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_MajorCustomersAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_df8a09fe-eea0-4eb9-af8d-777eda7e3243" xlink:to="loc_srt_MajorCustomersAxis_9317b9ad-ba81-4cb4-a2de-9e69ec8da41b" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_NameOfMajorCustomerDomain_9317b9ad-ba81-4cb4-a2de-9e69ec8da41b_default" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_NameOfMajorCustomerDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_MajorCustomersAxis_9317b9ad-ba81-4cb4-a2de-9e69ec8da41b" xlink:to="loc_srt_NameOfMajorCustomerDomain_9317b9ad-ba81-4cb4-a2de-9e69ec8da41b_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_NameOfMajorCustomerDomain_d5ce299b-ad0c-4d83-8ace-c38c796cc385" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_NameOfMajorCustomerDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_MajorCustomersAxis_9317b9ad-ba81-4cb4-a2de-9e69ec8da41b" xlink:to="loc_srt_NameOfMajorCustomerDomain_d5ce299b-ad0c-4d83-8ace-c38c796cc385" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember_6d7f453f-ca4a-4c21-ab04-ffe40b2c7668" xlink:href="wlkp-20211231.xsd#wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_NameOfMajorCustomerDomain_d5ce299b-ad0c-4d83-8ace-c38c796cc385" xlink:to="loc_wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember_6d7f453f-ca4a-4c21-ab04-ffe40b2c7668" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskByTypeAxis_32c9deb9-4ef7-4fe2-9ed0-ec7d36e4f4f5" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ConcentrationRiskByTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_df8a09fe-eea0-4eb9-af8d-777eda7e3243" xlink:to="loc_us-gaap_ConcentrationRiskByTypeAxis_32c9deb9-4ef7-4fe2-9ed0-ec7d36e4f4f5" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskTypeDomain_32c9deb9-4ef7-4fe2-9ed0-ec7d36e4f4f5_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ConcentrationRiskTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ConcentrationRiskByTypeAxis_32c9deb9-4ef7-4fe2-9ed0-ec7d36e4f4f5" xlink:to="loc_us-gaap_ConcentrationRiskTypeDomain_32c9deb9-4ef7-4fe2-9ed0-ec7d36e4f4f5_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskTypeDomain_c26e2939-cb37-4d5a-9846-5669b9d22ba9" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ConcentrationRiskTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ConcentrationRiskByTypeAxis_32c9deb9-4ef7-4fe2-9ed0-ec7d36e4f4f5" xlink:to="loc_us-gaap_ConcentrationRiskTypeDomain_c26e2939-cb37-4d5a-9846-5669b9d22ba9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CustomerConcentrationRiskMember_9e92a8de-c358-464a-93b7-2850d1d7b678" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CustomerConcentrationRiskMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConcentrationRiskTypeDomain_c26e2939-cb37-4d5a-9846-5669b9d22ba9" xlink:to="loc_us-gaap_CustomerConcentrationRiskMember_9e92a8de-c358-464a-93b7-2850d1d7b678" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_1d1a1f56-fd3c-4c7c-91ab-352ca18f2b4e" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_df8a09fe-eea0-4eb9-af8d-777eda7e3243" xlink:to="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_1d1a1f56-fd3c-4c7c-91ab-352ca18f2b4e" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_1d1a1f56-fd3c-4c7c-91ab-352ca18f2b4e_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_1d1a1f56-fd3c-4c7c-91ab-352ca18f2b4e" xlink:to="loc_us-gaap_RelatedPartyDomain_1d1a1f56-fd3c-4c7c-91ab-352ca18f2b4e_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_86ff9113-3151-42d1-914f-b22964776a5d" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_1d1a1f56-fd3c-4c7c-91ab-352ca18f2b4e" xlink:to="loc_us-gaap_RelatedPartyDomain_86ff9113-3151-42d1-914f-b22964776a5d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_AffiliatedEntityMember_e1262100-72fb-41c1-b7bc-0f6eed313b74" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_AffiliatedEntityMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyDomain_86ff9113-3151-42d1-914f-b22964776a5d" xlink:to="loc_srt_AffiliatedEntityMember_e1262100-72fb-41c1-b7bc-0f6eed313b74" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.westlake.com/role/DerivativeCommodityInstrumentsDetails" xlink:type="simple" xlink:href="wlkp-20211231.xsd#DerivativeCommodityInstrumentsDetails"/>
  <link:definitionLink xlink:role="http://www.westlake.com/role/DerivativeCommodityInstrumentsDetails" xlink:type="extended" id="ib7a8a96aaa114a26b501adf96c74b272_DerivativeCommodityInstrumentsDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeLineItems_94ad1a07-bc95-4407-9d44-4697aa7aed4b" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DerivativeLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeNonmonetaryNotionalAmountMass_8087b8e9-2856-49f8-a686-8fd3a0f32a9a" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DerivativeNonmonetaryNotionalAmountMass"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeLineItems_94ad1a07-bc95-4407-9d44-4697aa7aed4b" xlink:to="loc_us-gaap_DerivativeNonmonetaryNotionalAmountMass_8087b8e9-2856-49f8-a686-8fd3a0f32a9a" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeNonmonetaryNotionalAmountVolume_456dc1f5-beb3-4310-866f-794b492aae66" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DerivativeNonmonetaryNotionalAmountVolume"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeLineItems_94ad1a07-bc95-4407-9d44-4697aa7aed4b" xlink:to="loc_us-gaap_DerivativeNonmonetaryNotionalAmountVolume_456dc1f5-beb3-4310-866f-794b492aae66" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeLiabilitiesCurrent_176fa73d-d691-4738-8f3d-84ec0c61a58f" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DerivativeLiabilitiesCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeLineItems_94ad1a07-bc95-4407-9d44-4697aa7aed4b" xlink:to="loc_us-gaap_DerivativeLiabilitiesCurrent_176fa73d-d691-4738-8f3d-84ec0c61a58f" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeAssetsCurrent_133fa435-5564-43e5-a1f7-db45a50c866c" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DerivativeAssetsCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeLineItems_94ad1a07-bc95-4407-9d44-4697aa7aed4b" xlink:to="loc_us-gaap_DerivativeAssetsCurrent_133fa435-5564-43e5-a1f7-db45a50c866c" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GainOnDerivativeInstrumentsPretax_bd218d88-1e64-46e5-9451-6b271537ec58" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_GainOnDerivativeInstrumentsPretax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeLineItems_94ad1a07-bc95-4407-9d44-4697aa7aed4b" xlink:to="loc_us-gaap_GainOnDerivativeInstrumentsPretax_bd218d88-1e64-46e5-9451-6b271537ec58" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LossOnDerivativeInstrumentsPretax_838a2413-2624-425f-ae9f-7ae064fdc283" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LossOnDerivativeInstrumentsPretax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeLineItems_94ad1a07-bc95-4407-9d44-4697aa7aed4b" xlink:to="loc_us-gaap_LossOnDerivativeInstrumentsPretax_838a2413-2624-425f-ae9f-7ae064fdc283" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeTable_0f6c39b6-e99f-49a3-8cd1-3880886f92fc" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DerivativeTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DerivativeLineItems_94ad1a07-bc95-4407-9d44-4697aa7aed4b" xlink:to="loc_us-gaap_DerivativeTable_0f6c39b6-e99f-49a3-8cd1-3880886f92fc" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementLocationAxis_193a8987-359a-408a-bed0-6bcb5537b07a" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncomeStatementLocationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeTable_0f6c39b6-e99f-49a3-8cd1-3880886f92fc" xlink:to="loc_us-gaap_IncomeStatementLocationAxis_193a8987-359a-408a-bed0-6bcb5537b07a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementLocationDomain_193a8987-359a-408a-bed0-6bcb5537b07a_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncomeStatementLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_IncomeStatementLocationAxis_193a8987-359a-408a-bed0-6bcb5537b07a" xlink:to="loc_us-gaap_IncomeStatementLocationDomain_193a8987-359a-408a-bed0-6bcb5537b07a_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementLocationDomain_90a9fb81-99d6-4e41-a1c3-079dd26be18d" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncomeStatementLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_IncomeStatementLocationAxis_193a8987-359a-408a-bed0-6bcb5537b07a" xlink:to="loc_us-gaap_IncomeStatementLocationDomain_90a9fb81-99d6-4e41-a1c3-079dd26be18d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CostOfSalesMember_76fca3ff-7a02-49ad-8950-6aefe532b0f4" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CostOfSalesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementLocationDomain_90a9fb81-99d6-4e41-a1c3-079dd26be18d" xlink:to="loc_us-gaap_CostOfSalesMember_76fca3ff-7a02-49ad-8950-6aefe532b0f4" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SalesMember_2b0a6dcf-5795-419b-bd37-09af870d76fa" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SalesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementLocationDomain_90a9fb81-99d6-4e41-a1c3-079dd26be18d" xlink:to="loc_us-gaap_SalesMember_2b0a6dcf-5795-419b-bd37-09af870d76fa" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.westlake.com/role/UnitbasedCompensationDetails" xlink:type="simple" xlink:href="wlkp-20211231.xsd#UnitbasedCompensationDetails"/>
  <link:definitionLink xlink:role="http://www.westlake.com/role/UnitbasedCompensationDetails" xlink:type="extended" id="i1b795379b57048e3a6f1d8aa519278f6_UnitbasedCompensationDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_cb48f978-6be4-41ad-8962-7423527b71c8" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized_9ec89782-0a11-44af-8bac-f9987068aea8" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_cb48f978-6be4-41ad-8962-7423527b71c8" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized_9ec89782-0a11-44af-8bac-f9987068aea8" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardSharesIssuedInPeriod_48c9df48-392f-4d06-aecd-76439f26cfae" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardSharesIssuedInPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_cb48f978-6be4-41ad-8962-7423527b71c8" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardSharesIssuedInPeriod_48c9df48-392f-4d06-aecd-76439f26cfae" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_wlkp_DeferredCompensationArrangementwithIndividualNumberofDirectorsThatRetiredinPeriod_74a4285d-1673-4a1c-9b20-d697b60f0ab4" xlink:href="wlkp-20211231.xsd#wlkp_DeferredCompensationArrangementwithIndividualNumberofDirectorsThatRetiredinPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_cb48f978-6be4-41ad-8962-7423527b71c8" xlink:to="loc_wlkp_DeferredCompensationArrangementwithIndividualNumberofDirectorsThatRetiredinPeriod_74a4285d-1673-4a1c-9b20-d697b60f0ab4" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodTotalFairValue_182919cc-8d2c-449a-a03e-5d9df0f1e350" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodTotalFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_cb48f978-6be4-41ad-8962-7423527b71c8" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodTotalFairValue_182919cc-8d2c-449a-a03e-5d9df0f1e350" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsOutstandingRollForward_927f2738-2be2-4baf-a2e9-3b95b76a63a1" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsOutstandingRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_cb48f978-6be4-41ad-8962-7423527b71c8" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsOutstandingRollForward_927f2738-2be2-4baf-a2e9-3b95b76a63a1" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_293917ce-d123-4129-a15d-16b67c1ca088" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsOutstandingRollForward_927f2738-2be2-4baf-a2e9-3b95b76a63a1" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_293917ce-d123-4129-a15d-16b67c1ca088" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsGranted_22d35e23-5142-4f26-b697-e4ac47fc0a8a" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsGranted"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsOutstandingRollForward_927f2738-2be2-4baf-a2e9-3b95b76a63a1" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsGranted_22d35e23-5142-4f26-b697-e4ac47fc0a8a" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsExercised_7dd5c4ae-b951-4022-9044-4bad69d0de11" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsExercised"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsOutstandingRollForward_927f2738-2be2-4baf-a2e9-3b95b76a63a1" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsExercised_7dd5c4ae-b951-4022-9044-4bad69d0de11" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_7f303312-326d-4a81-b233-bf252c2fe220" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsNonvestedWeightedAverageGrantDateFairValueAbstract_742d9e07-e975-4895-ac2f-76e0a8a2d1fc" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsNonvestedWeightedAverageGrantDateFairValueAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_cb48f978-6be4-41ad-8962-7423527b71c8" xlink:to="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsNonvestedWeightedAverageGrantDateFairValueAbstract_742d9e07-e975-4895-ac2f-76e0a8a2d1fc" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue_148d939b-37a6-439a-83cf-d79833a064b1" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsNonvestedWeightedAverageGrantDateFairValueAbstract_742d9e07-e975-4895-ac2f-76e0a8a2d1fc" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue_148d939b-37a6-439a-83cf-d79833a064b1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_2bed3796-908e-4269-b0cc-390ed000957c" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsNonvestedWeightedAverageGrantDateFairValueAbstract_742d9e07-e975-4895-ac2f-76e0a8a2d1fc" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_2bed3796-908e-4269-b0cc-390ed000957c" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue_59290758-5be5-4dd6-bcf4-0d0a37c0151d" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsNonvestedWeightedAverageGrantDateFairValueAbstract_742d9e07-e975-4895-ac2f-76e0a8a2d1fc" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue_59290758-5be5-4dd6-bcf4-0d0a37c0151d" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue_325fc728-61ab-4605-a1e0-409fd921ae57" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant_938e4e08-1806-4683-bc24-a4f99ba42065" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_cb48f978-6be4-41ad-8962-7423527b71c8" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant_938e4e08-1806-4683-bc24-a4f99ba42065" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AllocatedShareBasedCompensationExpense_e5866c0d-2942-4583-b880-bab398afc556" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AllocatedShareBasedCompensationExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_cb48f978-6be4-41ad-8962-7423527b71c8" xlink:to="loc_us-gaap_AllocatedShareBasedCompensationExpense_e5866c0d-2942-4583-b880-bab398afc556" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedShareBasedAwardsOtherThanOptions_f07f2f56-99d7-4ad5-a36a-224a2c6fbc1b" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedShareBasedAwardsOtherThanOptions"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_cb48f978-6be4-41ad-8962-7423527b71c8" xlink:to="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedShareBasedAwardsOtherThanOptions_f07f2f56-99d7-4ad5-a36a-224a2c6fbc1b" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1_e8b9e5a6-d719-423b-b9db-1200dedb3f15" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_cb48f978-6be4-41ad-8962-7423527b71c8" xlink:to="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1_e8b9e5a6-d719-423b-b9db-1200dedb3f15" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_25f537c0-d687-448a-9863-0b88ee6c5b50" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_cb48f978-6be4-41ad-8962-7423527b71c8" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_25f537c0-d687-448a-9863-0b88ee6c5b50" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_TitleOfIndividualAxis_85b8d82e-187d-4a3e-ba04-a1a778a86561" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_TitleOfIndividualAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_25f537c0-d687-448a-9863-0b88ee6c5b50" xlink:to="loc_srt_TitleOfIndividualAxis_85b8d82e-187d-4a3e-ba04-a1a778a86561" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_TitleOfIndividualWithRelationshipToEntityDomain_85b8d82e-187d-4a3e-ba04-a1a778a86561_default" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_TitleOfIndividualWithRelationshipToEntityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_TitleOfIndividualAxis_85b8d82e-187d-4a3e-ba04-a1a778a86561" xlink:to="loc_srt_TitleOfIndividualWithRelationshipToEntityDomain_85b8d82e-187d-4a3e-ba04-a1a778a86561_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_TitleOfIndividualWithRelationshipToEntityDomain_5c49ada8-a157-47fa-9b26-e6fdf39c52a3" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_TitleOfIndividualWithRelationshipToEntityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_TitleOfIndividualAxis_85b8d82e-187d-4a3e-ba04-a1a778a86561" xlink:to="loc_srt_TitleOfIndividualWithRelationshipToEntityDomain_5c49ada8-a157-47fa-9b26-e6fdf39c52a3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_DirectorMember_d2753f30-5c05-473f-95e7-d906efc3a7e7" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_DirectorMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_TitleOfIndividualWithRelationshipToEntityDomain_5c49ada8-a157-47fa-9b26-e6fdf39c52a3" xlink:to="loc_srt_DirectorMember_d2753f30-5c05-473f-95e7-d906efc3a7e7" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PlanNameAxis_1620e393-9280-4a03-8596-3df06b864977" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PlanNameAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_25f537c0-d687-448a-9863-0b88ee6c5b50" xlink:to="loc_us-gaap_PlanNameAxis_1620e393-9280-4a03-8596-3df06b864977" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PlanNameDomain_1620e393-9280-4a03-8596-3df06b864977_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_PlanNameAxis_1620e393-9280-4a03-8596-3df06b864977" xlink:to="loc_us-gaap_PlanNameDomain_1620e393-9280-4a03-8596-3df06b864977_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PlanNameDomain_b86ab409-320b-4074-8500-e7a323fa7f89" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_PlanNameAxis_1620e393-9280-4a03-8596-3df06b864977" xlink:to="loc_us-gaap_PlanNameDomain_b86ab409-320b-4074-8500-e7a323fa7f89" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_wlkp_WestlakeChemicalPartnersLPLongTermIncentivePlanMember_45b0398c-03d9-4229-9022-d05259c9ef37" xlink:href="wlkp-20211231.xsd#wlkp_WestlakeChemicalPartnersLPLongTermIncentivePlanMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PlanNameDomain_b86ab409-320b-4074-8500-e7a323fa7f89" xlink:to="loc_wlkp_WestlakeChemicalPartnersLPLongTermIncentivePlanMember_45b0398c-03d9-4229-9022-d05259c9ef37" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AwardTypeAxis_dd66b8ef-6baa-4c33-99ae-5df8a8ff0835" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AwardTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_25f537c0-d687-448a-9863-0b88ee6c5b50" xlink:to="loc_us-gaap_AwardTypeAxis_dd66b8ef-6baa-4c33-99ae-5df8a8ff0835" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_dd66b8ef-6baa-4c33-99ae-5df8a8ff0835_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AwardTypeAxis_dd66b8ef-6baa-4c33-99ae-5df8a8ff0835" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_dd66b8ef-6baa-4c33-99ae-5df8a8ff0835_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_eec9bfc0-8b9d-4589-ae23-9861bef14076" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AwardTypeAxis_dd66b8ef-6baa-4c33-99ae-5df8a8ff0835" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_eec9bfc0-8b9d-4589-ae23-9861bef14076" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PhantomShareUnitsPSUsMember_4b682830-82eb-4f26-a8fe-272d62fe95aa" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PhantomShareUnitsPSUsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_eec9bfc0-8b9d-4589-ae23-9861bef14076" xlink:to="loc_us-gaap_PhantomShareUnitsPSUsMember_4b682830-82eb-4f26-a8fe-272d62fe95aa" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementLocationAxis_fe87a9aa-ade1-49ca-a8cc-ea10c220fca8" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncomeStatementLocationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_25f537c0-d687-448a-9863-0b88ee6c5b50" xlink:to="loc_us-gaap_IncomeStatementLocationAxis_fe87a9aa-ade1-49ca-a8cc-ea10c220fca8" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementLocationDomain_fe87a9aa-ade1-49ca-a8cc-ea10c220fca8_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncomeStatementLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_IncomeStatementLocationAxis_fe87a9aa-ade1-49ca-a8cc-ea10c220fca8" xlink:to="loc_us-gaap_IncomeStatementLocationDomain_fe87a9aa-ade1-49ca-a8cc-ea10c220fca8_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementLocationDomain_171e2df8-1fbb-4924-a30e-ec2ad9d06d99" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncomeStatementLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_IncomeStatementLocationAxis_fe87a9aa-ade1-49ca-a8cc-ea10c220fca8" xlink:to="loc_us-gaap_IncomeStatementLocationDomain_171e2df8-1fbb-4924-a30e-ec2ad9d06d99" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SellingGeneralAndAdministrativeExpensesMember_ab01681c-9e08-496f-9d65-7e2617cfe0af" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SellingGeneralAndAdministrativeExpensesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementLocationDomain_171e2df8-1fbb-4924-a30e-ec2ad9d06d99" xlink:to="loc_us-gaap_SellingGeneralAndAdministrativeExpensesMember_ab01681c-9e08-496f-9d65-7e2617cfe0af" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.westlake.com/role/FairValueMeasurementsScheduleOfCarryingAndFairValuesOfLongTermDebtDetails" xlink:type="simple" xlink:href="wlkp-20211231.xsd#FairValueMeasurementsScheduleOfCarryingAndFairValuesOfLongTermDebtDetails"/>
  <link:definitionLink xlink:role="http://www.westlake.com/role/FairValueMeasurementsScheduleOfCarryingAndFairValuesOfLongTermDebtDetails" xlink:type="extended" id="i19ed2d67a0124edeb89739c60cd28df5_FairValueMeasurementsScheduleOfCarryingAndFairValuesOfLongTermDebtDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_705e2847-79d7-45e9-b13f-9db0feb993ce" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DueToRelatedPartiesNoncurrent_1c7b63aa-ff9e-4691-9b81-b82f2b1e3d38" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DueToRelatedPartiesNoncurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_705e2847-79d7-45e9-b13f-9db0feb993ce" xlink:to="loc_us-gaap_DueToRelatedPartiesNoncurrent_1c7b63aa-ff9e-4691-9b81-b82f2b1e3d38" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebtFairValue_02afa020-7670-4532-b4bd-32411244cfd3" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LongTermDebtFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_705e2847-79d7-45e9-b13f-9db0feb993ce" xlink:to="loc_us-gaap_LongTermDebtFairValue_02afa020-7670-4532-b4bd-32411244cfd3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByBalanceSheetGroupingTable_6c3b8b51-a087-4def-b737-963eee71943a" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueByBalanceSheetGroupingTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_705e2847-79d7-45e9-b13f-9db0feb993ce" xlink:to="loc_us-gaap_FairValueByBalanceSheetGroupingTable_6c3b8b51-a087-4def-b737-963eee71943a" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentAxis_1b4d413a-df46-4235-9ef8-d2fee1e5acb5" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueByBalanceSheetGroupingTable_6c3b8b51-a087-4def-b737-963eee71943a" xlink:to="loc_us-gaap_DebtInstrumentAxis_1b4d413a-df46-4235-9ef8-d2fee1e5acb5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_1b4d413a-df46-4235-9ef8-d2fee1e5acb5_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DebtInstrumentAxis_1b4d413a-df46-4235-9ef8-d2fee1e5acb5" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_1b4d413a-df46-4235-9ef8-d2fee1e5acb5_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_6692c7e5-9047-4311-aab6-728c1f896021" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DebtInstrumentAxis_1b4d413a-df46-4235-9ef8-d2fee1e5acb5" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_6692c7e5-9047-4311-aab6-728c1f896021" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_wlkp_OpCoRevolverMember_3d2483ff-4134-442a-8203-e1f986cb63be" xlink:href="wlkp-20211231.xsd#wlkp_OpCoRevolverMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_6692c7e5-9047-4311-aab6-728c1f896021" xlink:to="loc_wlkp_OpCoRevolverMember_3d2483ff-4134-442a-8203-e1f986cb63be" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_wlkp_MLPRevolverMember_1f5ab0db-81b7-484c-8278-4010eea392bb" xlink:href="wlkp-20211231.xsd#wlkp_MLPRevolverMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_6692c7e5-9047-4311-aab6-728c1f896021" xlink:to="loc_wlkp_MLPRevolverMember_1f5ab0db-81b7-484c-8278-4010eea392bb" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeAxis_9d2ccc92-ec6e-4d78-91ad-dad43fd32666" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LongtermDebtTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueByBalanceSheetGroupingTable_6c3b8b51-a087-4def-b737-963eee71943a" xlink:to="loc_us-gaap_LongtermDebtTypeAxis_9d2ccc92-ec6e-4d78-91ad-dad43fd32666" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_9d2ccc92-ec6e-4d78-91ad-dad43fd32666_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_9d2ccc92-ec6e-4d78-91ad-dad43fd32666" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_9d2ccc92-ec6e-4d78-91ad-dad43fd32666_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_a1937c85-136f-478b-a8b3-2805d17a52e4" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_9d2ccc92-ec6e-4d78-91ad-dad43fd32666" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_a1937c85-136f-478b-a8b3-2805d17a52e4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_wlkp_SeniorUnsecuredRevolvingCreditFacilityMember_1ef0157d-521a-444d-8f9c-91809a95c145" xlink:href="wlkp-20211231.xsd#wlkp_SeniorUnsecuredRevolvingCreditFacilityMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_a1937c85-136f-478b-a8b3-2805d17a52e4" xlink:to="loc_wlkp_SeniorUnsecuredRevolvingCreditFacilityMember_1ef0157d-521a-444d-8f9c-91809a95c145" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.westlake.com/role/SupplementalInformationCashFlowInformationDetails" xlink:type="simple" xlink:href="wlkp-20211231.xsd#SupplementalInformationCashFlowInformationDetails"/>
  <link:definitionLink xlink:role="http://www.westlake.com/role/SupplementalInformationCashFlowInformationDetails" xlink:type="extended" id="ia6f2e0238b194334bb53e931738f9959_SupplementalInformationCashFlowInformationDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionLineItems_3b9eff5c-f13b-41cd-b1e7-7599c1c8ab58" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RelatedPartyTransactionLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CapitalExpendituresIncurredButNotYetPaid_f9f3b5f9-dfac-41c5-a6d1-0ddf9b81de20" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CapitalExpendituresIncurredButNotYetPaid"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_3b9eff5c-f13b-41cd-b1e7-7599c1c8ab58" xlink:to="loc_us-gaap_CapitalExpendituresIncurredButNotYetPaid_f9f3b5f9-dfac-41c5-a6d1-0ddf9b81de20" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestPaidNet_32ac3084-2766-4b25-a57a-05ead7c62745" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_InterestPaidNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_3b9eff5c-f13b-41cd-b1e7-7599c1c8ab58" xlink:to="loc_us-gaap_InterestPaidNet_32ac3084-2766-4b25-a57a-05ead7c62745" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxesPaid_d147eff9-364b-47c9-9c88-21731f05374b" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncomeTaxesPaid"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_3b9eff5c-f13b-41cd-b1e7-7599c1c8ab58" xlink:to="loc_us-gaap_IncomeTaxesPaid_d147eff9-364b-47c9-9c88-21731f05374b" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_f998c4b6-e058-4f64-8d0e-025cd7eef19b" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_3b9eff5c-f13b-41cd-b1e7-7599c1c8ab58" xlink:to="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_f998c4b6-e058-4f64-8d0e-025cd7eef19b" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionAxis_4bc3dc17-b905-4130-9174-7990b3d5ec97" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RelatedPartyTransactionAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_f998c4b6-e058-4f64-8d0e-025cd7eef19b" xlink:to="loc_us-gaap_RelatedPartyTransactionAxis_4bc3dc17-b905-4130-9174-7990b3d5ec97" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionDomain_4bc3dc17-b905-4130-9174-7990b3d5ec97_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RelatedPartyTransactionDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RelatedPartyTransactionAxis_4bc3dc17-b905-4130-9174-7990b3d5ec97" xlink:to="loc_us-gaap_RelatedPartyTransactionDomain_4bc3dc17-b905-4130-9174-7990b3d5ec97_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionDomain_84760718-cafa-4f80-8467-1c566c86be11" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RelatedPartyTransactionDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RelatedPartyTransactionAxis_4bc3dc17-b905-4130-9174-7990b3d5ec97" xlink:to="loc_us-gaap_RelatedPartyTransactionDomain_84760718-cafa-4f80-8467-1c566c86be11" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_wlkp_ReimbursementtoParentforStateTaxMember_6ee3b9b2-11b1-4ee7-8226-820de214798d" xlink:href="wlkp-20211231.xsd#wlkp_ReimbursementtoParentforStateTaxMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionDomain_84760718-cafa-4f80-8467-1c566c86be11" xlink:to="loc_wlkp_ReimbursementtoParentforStateTaxMember_6ee3b9b2-11b1-4ee7-8226-820de214798d" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxAuthorityAxis_c3285140-8137-4c68-ba1e-d01934b9c625" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncomeTaxAuthorityAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_f998c4b6-e058-4f64-8d0e-025cd7eef19b" xlink:to="loc_us-gaap_IncomeTaxAuthorityAxis_c3285140-8137-4c68-ba1e-d01934b9c625" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxAuthorityDomain_c3285140-8137-4c68-ba1e-d01934b9c625_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncomeTaxAuthorityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_IncomeTaxAuthorityAxis_c3285140-8137-4c68-ba1e-d01934b9c625" xlink:to="loc_us-gaap_IncomeTaxAuthorityDomain_c3285140-8137-4c68-ba1e-d01934b9c625_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxAuthorityDomain_737a3828-92cb-4bf1-86b4-c5303d805516" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncomeTaxAuthorityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_IncomeTaxAuthorityAxis_c3285140-8137-4c68-ba1e-d01934b9c625" xlink:to="loc_us-gaap_IncomeTaxAuthorityDomain_737a3828-92cb-4bf1-86b4-c5303d805516" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StateAndLocalJurisdictionMember_493f2c04-2002-488e-a4c1-df071316529b" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StateAndLocalJurisdictionMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeTaxAuthorityDomain_737a3828-92cb-4bf1-86b4-c5303d805516" xlink:to="loc_us-gaap_StateAndLocalJurisdictionMember_493f2c04-2002-488e-a4c1-df071316529b" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CounterpartyNameAxis_f3fe367a-d2d1-4a26-b17f-b928c8d513c8" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_CounterpartyNameAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_f998c4b6-e058-4f64-8d0e-025cd7eef19b" xlink:to="loc_srt_CounterpartyNameAxis_f3fe367a-d2d1-4a26-b17f-b928c8d513c8" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RepurchaseAgreementCounterpartyNameDomain_f3fe367a-d2d1-4a26-b17f-b928c8d513c8_default" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RepurchaseAgreementCounterpartyNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_CounterpartyNameAxis_f3fe367a-d2d1-4a26-b17f-b928c8d513c8" xlink:to="loc_srt_RepurchaseAgreementCounterpartyNameDomain_f3fe367a-d2d1-4a26-b17f-b928c8d513c8_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RepurchaseAgreementCounterpartyNameDomain_69c25144-25e9-41db-8781-6ef30d4e14ec" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RepurchaseAgreementCounterpartyNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_CounterpartyNameAxis_f3fe367a-d2d1-4a26-b17f-b928c8d513c8" xlink:to="loc_srt_RepurchaseAgreementCounterpartyNameDomain_69c25144-25e9-41db-8781-6ef30d4e14ec" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember_d3167656-dc8d-4b2e-bcd1-da6d621b9f3f" xlink:href="wlkp-20211231.xsd#wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RepurchaseAgreementCounterpartyNameDomain_69c25144-25e9-41db-8781-6ef30d4e14ec" xlink:to="loc_wlkp_ParentCompanyAndSubsidiariesExcludingReportingEntityAndSubsidiariesMember_d3167656-dc8d-4b2e-bcd1-da6d621b9f3f" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_010b4e45-f116-4430-94cf-720ebfea8c75" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_f998c4b6-e058-4f64-8d0e-025cd7eef19b" xlink:to="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_010b4e45-f116-4430-94cf-720ebfea8c75" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_010b4e45-f116-4430-94cf-720ebfea8c75_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_010b4e45-f116-4430-94cf-720ebfea8c75" xlink:to="loc_us-gaap_RelatedPartyDomain_010b4e45-f116-4430-94cf-720ebfea8c75_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_f6d8fd17-3a1d-44f1-988e-7f612d3a7dd0" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_010b4e45-f116-4430-94cf-720ebfea8c75" xlink:to="loc_us-gaap_RelatedPartyDomain_f6d8fd17-3a1d-44f1-988e-7f612d3a7dd0" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_AffiliatedEntityMember_7d670c73-0caa-4f84-ad42-1911345dcb4b" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_AffiliatedEntityMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyDomain_f6d8fd17-3a1d-44f1-988e-7f612d3a7dd0" xlink:to="loc_srt_AffiliatedEntityMember_7d670c73-0caa-4f84-ad42-1911345dcb4b" xlink:type="arc" order="0"/>
  </link:definitionLink>
</link:linkbase>
