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

<!--XBRL Document Created with the Workiva Platform-->
<!--Copyright 2026 Workiva-->
<!--r:019b2d7f-efd7-7525-accc-2dc9ce14caef,g:595941cb-b6ec-4e3d-87fa-72673740eaa6-->
<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema" xmlns:link="http://www.xbrl.org/2003/linkbase" xmlns:wlk="http://www.westlake.com/20260331" xmlns:xbrli="http://www.xbrl.org/2003/instance" xmlns:dtr-types="http://www.xbrl.org/dtr/type/2024-01-31" xmlns:xbrldt="http://xbrl.org/2005/xbrldt" attributeFormDefault="unqualified" elementFormDefault="qualified" targetNamespace="http://www.westlake.com/20260331">
  <xs:import namespace="http://fasb.org/srt/2025" schemaLocation="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd"/>
  <xs:import namespace="http://fasb.org/us-gaap/2025" schemaLocation="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd"/>
  <xs:import namespace="http://www.xbrl.org/2003/instance" schemaLocation="http://www.xbrl.org/2003/xbrl-instance-2003-12-31.xsd"/>
  <xs:import namespace="http://www.xbrl.org/2003/linkbase" schemaLocation="http://www.xbrl.org/2003/xbrl-linkbase-2003-12-31.xsd"/>
  <xs:import namespace="http://www.xbrl.org/dtr/type/2024-01-31" schemaLocation="https://www.xbrl.org/dtr/type/2024-01-31/types.xsd"/>
  <xs:import namespace="http://xbrl.org/2005/xbrldt" schemaLocation="http://www.xbrl.org/2005/xbrldt-2005.xsd"/>
  <xs:import namespace="http://xbrl.sec.gov/dei/2025" schemaLocation="https://xbrl.sec.gov/dei/2025/dei-2025.xsd"/>
  <xs:import namespace="http://xbrl.sec.gov/ecd/2025" schemaLocation="https://xbrl.sec.gov/ecd/2025/ecd-2025.xsd"/>
  <xs:annotation>
    <xs:appinfo>
      <link:linkbaseRef xmlns:xlink="http://www.w3.org/1999/xlink" xlink:arcrole="http://www.w3.org/1999/xlink/properties/linkbase" xlink:href="wlk-20260331_pre.xml" xlink:role="http://www.xbrl.org/2003/role/presentationLinkbaseRef" xlink:type="simple"/>
      <link:linkbaseRef xmlns:xlink="http://www.w3.org/1999/xlink" xlink:arcrole="http://www.w3.org/1999/xlink/properties/linkbase" xlink:href="wlk-20260331_def.xml" xlink:role="http://www.xbrl.org/2003/role/definitionLinkbaseRef" xlink:type="simple"/>
      <link:linkbaseRef xmlns:xlink="http://www.w3.org/1999/xlink" xlink:arcrole="http://www.w3.org/1999/xlink/properties/linkbase" xlink:href="wlk-20260331_lab.xml" xlink:role="http://www.xbrl.org/2003/role/labelLinkbaseRef" xlink:type="simple"/>
      <link:linkbaseRef xmlns:xlink="http://www.w3.org/1999/xlink" xlink:arcrole="http://www.w3.org/1999/xlink/properties/linkbase" xlink:href="wlk-20260331_cal.xml" xlink:role="http://www.xbrl.org/2003/role/calculationLinkbaseRef" xlink:type="simple"/>
      <link:roleType id="CoverPage" roleURI="http://www.westlake.com/role/CoverPage">
        <link:definition>0000001 - Document - Cover Page</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="ConsolidatedBalanceSheetsUnaudited" roleURI="http://www.westlake.com/role/ConsolidatedBalanceSheetsUnaudited">
        <link:definition>9952151 - Statement - Consolidated Balance Sheets (Unaudited)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="ConsolidatedBalanceSheetsUnauditedParenthetical" roleURI="http://www.westlake.com/role/ConsolidatedBalanceSheetsUnauditedParenthetical">
        <link:definition>9952152 - Statement - Consolidated Balance Sheets (Unaudited) (Parenthetical)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="ConsolidatedStatementsofOperationsUnaudited" roleURI="http://www.westlake.com/role/ConsolidatedStatementsofOperationsUnaudited">
        <link:definition>9952153 - Statement - Consolidated Statements of Operations (Unaudited)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="ConsolidatedStatementsofComprehensiveLossUnaudited" roleURI="http://www.westlake.com/role/ConsolidatedStatementsofComprehensiveLossUnaudited">
        <link:definition>9952154 - Statement - Consolidated Statements of Comprehensive Loss (Unaudited)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="ConsolidatedStatementsofComprehensiveIncomeUnauditedParenthetical" roleURI="http://www.westlake.com/role/ConsolidatedStatementsofComprehensiveIncomeUnauditedParenthetical">
        <link:definition>9952155 - Statement - Consolidated Statements of Comprehensive Income (Unaudited) (Parenthetical)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="ConsolidatedStatementsOfChangesInStockholdersEquity" roleURI="http://www.westlake.com/role/ConsolidatedStatementsOfChangesInStockholdersEquity">
        <link:definition>9952156 - Statement - Consolidated Statements Of Changes In Stockholders' Equity</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="ConsolidatedStatementsofCashFlowsUnaudited" roleURI="http://www.westlake.com/role/ConsolidatedStatementsofCashFlowsUnaudited">
        <link:definition>9952157 - Statement - Consolidated Statements of Cash Flows (Unaudited)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="DescriptionofBusinessandBasisofPresentation" roleURI="http://www.westlake.com/role/DescriptionofBusinessandBasisofPresentation">
        <link:definition>9952158 - Disclosure - Description of Business and Basis of Presentation</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="Acquisitions" roleURI="http://www.westlake.com/role/Acquisitions">
        <link:definition>9952159 - Disclosure - Acquisitions</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="FinancialInstruments" roleURI="http://www.westlake.com/role/FinancialInstruments">
        <link:definition>9952160 - Disclosure - Financial Instruments</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="AccountsReceivable" roleURI="http://www.westlake.com/role/AccountsReceivable">
        <link:definition>9952161 - Disclosure - Accounts Receivable</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="Inventories" roleURI="http://www.westlake.com/role/Inventories">
        <link:definition>9952162 - Disclosure - Inventories</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="Goodwill" roleURI="http://www.westlake.com/role/Goodwill">
        <link:definition>9952163 - Disclosure - Goodwill</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="AccountsPayable" roleURI="http://www.westlake.com/role/AccountsPayable">
        <link:definition>9952164 - Disclosure - Accounts Payable</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="LongTermDebt" roleURI="http://www.westlake.com/role/LongTermDebt">
        <link:definition>9952165 - Disclosure - Long-Term Debt</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="AccumulatedOtherComprehensiveLoss" roleURI="http://www.westlake.com/role/AccumulatedOtherComprehensiveLoss">
        <link:definition>9952166 - Disclosure - Accumulated Other Comprehensive Loss</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="FairValueMeasurements" roleURI="http://www.westlake.com/role/FairValueMeasurements">
        <link:definition>9952167 - Disclosure - Fair Value Measurements</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="IncomeTaxes" roleURI="http://www.westlake.com/role/IncomeTaxes">
        <link:definition>9952168 - Disclosure - Income Taxes</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="LossandDividendsperShare" roleURI="http://www.westlake.com/role/LossandDividendsperShare">
        <link:definition>9952169 - Disclosure - Loss and Dividends per Share</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="SupplementalInformation" roleURI="http://www.westlake.com/role/SupplementalInformation">
        <link:definition>9952170 - Disclosure - Supplemental Information</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="CommitmentsandContingencies" roleURI="http://www.westlake.com/role/CommitmentsandContingencies">
        <link:definition>9952171 - Disclosure - Commitments and Contingencies</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="SegmentInformation" roleURI="http://www.westlake.com/role/SegmentInformation">
        <link:definition>9952172 - Disclosure - Segment Information</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="WestlakeChemicalPartnersLP" roleURI="http://www.westlake.com/role/WestlakeChemicalPartnersLP">
        <link:definition>9952173 - Disclosure - Westlake Chemical Partners LP</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="DescriptionofBusinessandBasisofPresentationPolicies" roleURI="http://www.westlake.com/role/DescriptionofBusinessandBasisofPresentationPolicies">
        <link:definition>9955511 - Disclosure - Description of Business and Basis of Presentation (Policies)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="AcquisitionsTables" roleURI="http://www.westlake.com/role/AcquisitionsTables">
        <link:definition>9955512 - Disclosure - Acquisitions (Tables)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="FinancialInstrumentsTables" roleURI="http://www.westlake.com/role/FinancialInstrumentsTables">
        <link:definition>9955513 - Disclosure - Financial Instruments (Tables)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="AccountsReceivableTables" roleURI="http://www.westlake.com/role/AccountsReceivableTables">
        <link:definition>9955514 - Disclosure - Accounts Receivable (Tables)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="InventoriesTables" roleURI="http://www.westlake.com/role/InventoriesTables">
        <link:definition>9955515 - Disclosure - Inventories (Tables)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="GoodwillTables" roleURI="http://www.westlake.com/role/GoodwillTables">
        <link:definition>9955516 - Disclosure - Goodwill (Tables)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="AccountsPayableTables" roleURI="http://www.westlake.com/role/AccountsPayableTables">
        <link:definition>9955517 - Disclosure - Accounts Payable (Tables)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="LongTermDebtTables" roleURI="http://www.westlake.com/role/LongTermDebtTables">
        <link:definition>9955518 - Disclosure - Long-Term Debt (Tables)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="AccumulatedOtherComprehensiveLossTables" roleURI="http://www.westlake.com/role/AccumulatedOtherComprehensiveLossTables">
        <link:definition>9955519 - Disclosure - Accumulated Other Comprehensive Loss (Tables)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="FairValueMeasurementsTables" roleURI="http://www.westlake.com/role/FairValueMeasurementsTables">
        <link:definition>9955520 - Disclosure - Fair Value Measurements (Tables)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="LossandDividendsperShareTables" roleURI="http://www.westlake.com/role/LossandDividendsperShareTables">
        <link:definition>9955521 - Disclosure - Loss and Dividends per Share (Tables)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="SupplementalInformationTables" roleURI="http://www.westlake.com/role/SupplementalInformationTables">
        <link:definition>9955522 - Disclosure - Supplemental Information (Tables)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="SegmentInformationTables" roleURI="http://www.westlake.com/role/SegmentInformationTables">
        <link:definition>9955523 - Disclosure - Segment Information (Tables)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="AcquisitionsNarrativeDetails" roleURI="http://www.westlake.com/role/AcquisitionsNarrativeDetails">
        <link:definition>9955524 - Disclosure - Acquisitions - Narrative (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="FinancialInstrumentsNarrativeDetails" roleURI="http://www.westlake.com/role/FinancialInstrumentsNarrativeDetails">
        <link:definition>9955525 - Disclosure - Financial Instruments (Narrative) (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="FinancialInstrumentsAvailableForSaleDebtSecuritiesDetails" roleURI="http://www.westlake.com/role/FinancialInstrumentsAvailableForSaleDebtSecuritiesDetails">
        <link:definition>9955526 - Disclosure - Financial Instruments (Available-For-Sale Debt Securities) (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="FinancialInstrumentsCostandFairValueofAvailableForSaleDebtSecuritiesDetails" roleURI="http://www.westlake.com/role/FinancialInstrumentsCostandFairValueofAvailableForSaleDebtSecuritiesDetails">
        <link:definition>9955527 - Disclosure - Financial Instruments (Cost and Fair Value of Available-For-Sale Debt Securities) (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="AccountsReceivableDetails" roleURI="http://www.westlake.com/role/AccountsReceivableDetails">
        <link:definition>9955528 - Disclosure - Accounts Receivable (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="InventoriesDetails" roleURI="http://www.westlake.com/role/InventoriesDetails">
        <link:definition>9955529 - Disclosure - Inventories (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="GoodwillGoodwillDetails" roleURI="http://www.westlake.com/role/GoodwillGoodwillDetails">
        <link:definition>9955530 - Disclosure - Goodwill (Goodwill) (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="GoodwillNarrativeDetails" roleURI="http://www.westlake.com/role/GoodwillNarrativeDetails">
        <link:definition>9955531 - Disclosure - Goodwill (Narrative) (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="AccountsPayableDetails" roleURI="http://www.westlake.com/role/AccountsPayableDetails">
        <link:definition>9955532 - Disclosure - Accounts Payable (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="LongTermDebtScheduleofLongtermDebtDetails" roleURI="http://www.westlake.com/role/LongTermDebtScheduleofLongtermDebtDetails">
        <link:definition>9955533 - Disclosure - Long-Term Debt (Schedule of Long-term Debt) (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="LongTermDebtScheduleofLongtermDebtDetails_1" roleURI="http://www.westlake.com/role/LongTermDebtScheduleofLongtermDebtDetails_1">
        <link:definition>9955533 - Disclosure - Long-Term Debt (Schedule of Long-term Debt) (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="LongTermDebtNarrativeDetails" roleURI="http://www.westlake.com/role/LongTermDebtNarrativeDetails">
        <link:definition>9955534 - Disclosure - Long-Term Debt (Narrative) (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="LongTermDebtCreditAgreementDetails" roleURI="http://www.westlake.com/role/LongTermDebtCreditAgreementDetails">
        <link:definition>9955535 - Disclosure - Long-Term Debt (Credit Agreement) (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="AccumulatedOtherComprehensiveLossScheduleofAccumulatedOtherComprehensiveIncomeLossDetails" roleURI="http://www.westlake.com/role/AccumulatedOtherComprehensiveLossScheduleofAccumulatedOtherComprehensiveIncomeLossDetails">
        <link:definition>9955536 - Disclosure - Accumulated Other Comprehensive Loss (Schedule of Accumulated Other Comprehensive Income (Loss)) (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="FairValueMeasurementsSummaryofCarryingandFairValuesofLongTermDebtDetails" roleURI="http://www.westlake.com/role/FairValueMeasurementsSummaryofCarryingandFairValuesofLongTermDebtDetails">
        <link:definition>9955537 - Disclosure - Fair Value Measurements (Summary of Carrying and Fair Values of Long Term Debt) (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="IncomeTaxesDetails" roleURI="http://www.westlake.com/role/IncomeTaxesDetails">
        <link:definition>9955538 - Disclosure - Income Taxes (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="LossandDividendsperShareScheduleofNetIncomeAttributabletoCommonStockholdersDetails" roleURI="http://www.westlake.com/role/LossandDividendsperShareScheduleofNetIncomeAttributabletoCommonStockholdersDetails">
        <link:definition>9955539 - Disclosure - Loss and Dividends per Share (Schedule of Net Income Attributable to Common Stockholders) (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="LossandDividendsperShareReconciliationofDenominatorforBasicandDilutedEarningsPerShareDetails" roleURI="http://www.westlake.com/role/LossandDividendsperShareReconciliationofDenominatorforBasicandDilutedEarningsPerShareDetails">
        <link:definition>9955540 - Disclosure - Loss and Dividends per Share (Reconciliation of Denominator for Basic and Diluted Earnings Per Share) (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="LossandDividendsperShareAdditionalInformationDetails" roleURI="http://www.westlake.com/role/LossandDividendsperShareAdditionalInformationDetails">
        <link:definition>9955541 - Disclosure - Loss and Dividends per Share (Additional Information) (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="LossandDividendsperShareDividendsperShareDetails" roleURI="http://www.westlake.com/role/LossandDividendsperShareDividendsperShareDetails">
        <link:definition>9955542 - Disclosure - Loss and Dividends per Share (Dividends per Share) (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="SupplementalInformationEquityMethodInvestmentsDetails" roleURI="http://www.westlake.com/role/SupplementalInformationEquityMethodInvestmentsDetails">
        <link:definition>9955543 - Disclosure - Supplemental Information (Equity Method Investments) (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="SupplementalInformationAdditionalInformationDetails" roleURI="http://www.westlake.com/role/SupplementalInformationAdditionalInformationDetails">
        <link:definition>9955544 - Disclosure - Supplemental Information (Additional Information) (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="SupplementalInformationAdditionalInformationDetails_1" roleURI="http://www.westlake.com/role/SupplementalInformationAdditionalInformationDetails_1">
        <link:definition>9955544 - Disclosure - Supplemental Information (Additional Information) (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="SupplementalInformationContractLiabilitiesDetails" roleURI="http://www.westlake.com/role/SupplementalInformationContractLiabilitiesDetails">
        <link:definition>9955545 - Disclosure - Supplemental Information (Contract Liabilities) (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="SupplementalInformationRestructuringAccrualActivityDetails" roleURI="http://www.westlake.com/role/SupplementalInformationRestructuringAccrualActivityDetails">
        <link:definition>9955546 - Disclosure - Supplemental Information (Restructuring Accrual Activity) (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="SupplementalInformationSupplementalCashFlowInformationDetails" roleURI="http://www.westlake.com/role/SupplementalInformationSupplementalCashFlowInformationDetails">
        <link:definition>9955547 - Disclosure - Supplemental Information (Supplemental Cash Flow Information) (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="CommitmentsandContingenciesAdditionalInformationDetails" roleURI="http://www.westlake.com/role/CommitmentsandContingenciesAdditionalInformationDetails">
        <link:definition>9955548 - Disclosure - Commitments and Contingencies (Additional Information) (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="SegmentInformationAdditionalInformationDetail" roleURI="http://www.westlake.com/role/SegmentInformationAdditionalInformationDetail">
        <link:definition>9955549 - Disclosure - Segment Information (Additional Information) (Detail)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="SegmentInformationSegmentReportingInformationDetails" roleURI="http://www.westlake.com/role/SegmentInformationSegmentReportingInformationDetails">
        <link:definition>9955550 - Disclosure - Segment Information (Segment Reporting Information) (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="SegmentInformationReconciliationofTotalSegmentIncomefromOperationstoConsolidatedIncomebeforeIncomeTaxesDetails" roleURI="http://www.westlake.com/role/SegmentInformationReconciliationofTotalSegmentIncomefromOperationstoConsolidatedIncomebeforeIncomeTaxesDetails">
        <link:definition>9955551 - Disclosure - Segment Information (Reconciliation of Total Segment Income from Operations to Consolidated Income before Income Taxes) (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="SegmentInformationTotalAssetsDetails" roleURI="http://www.westlake.com/role/SegmentInformationTotalAssetsDetails">
        <link:definition>9955552 - Disclosure - Segment Information (Total Assets) (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="WestlakeChemicalPartnersLPDetails" roleURI="http://www.westlake.com/role/WestlakeChemicalPartnersLPDetails">
        <link:definition>9955553 - Disclosure - Westlake Chemical Partners LP (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
    </xs:appinfo>
  </xs:annotation>
  <xs:element id="wlk_OnePointSixTwoFivePercentageSeniorNotesDueTwentyTwentyNineMember" abstract="true" name="OnePointSixTwoFivePercentageSeniorNotesDueTwentyTwentyNineMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="wlk_ReturnOfAdditionsToInvestmentFromUnconsolidatedSubsidiaries" abstract="false" name="ReturnOfAdditionsToInvestmentFromUnconsolidatedSubsidiaries" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="wlk_EarningsandDividendsPerShareAbstract" abstract="true" name="EarningsandDividendsPerShareAbstract" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:stringItemType"/>
  <xs:element id="wlk_EarningsandDividendsPerShareTextBlock" abstract="false" name="EarningsandDividendsPerShareTextBlock" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:textBlockItemType"/>
  <xs:element id="wlk_ScheduleOfNetIncomeLossAttributableToCommonStockholdersTableTextBlock" abstract="false" name="ScheduleOfNetIncomeLossAttributableToCommonStockholdersTableTextBlock" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:textBlockItemType"/>
  <xs:element id="wlk_DividendsPerShareTableTextBlock" abstract="false" name="DividendsPerShareTableTextBlock" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:textBlockItemType"/>
  <xs:element id="wlk_ACIMember" abstract="true" name="ACIMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="wlk_PaymentsToAcquireBusinessesAccrued" abstract="false" name="PaymentsToAcquireBusinessesAccrued" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="wlk_SupranationalSecuritiesMember" abstract="true" name="SupranationalSecuritiesMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="wlk_HousingAndInfrastructureProductsMember" abstract="true" name="HousingAndInfrastructureProductsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="wlk_PerformanceAndEssentialMaterialsMember" abstract="true" name="PerformanceAndEssentialMaterialsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="wlk_WasteDisposalRevenueBondsDueTwentyTwentySevenMember" abstract="true" name="WasteDisposalRevenueBondsDueTwentyTwentySevenMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="wlk_ThreePointSixPercentSeniorNotesDueTwentyTwentySixMember" abstract="true" name="ThreePointSixPercentSeniorNotesDueTwentyTwentySixMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="wlk_ThreePointThreeSevenFiveSeniorNotesDueTwentyThirtyMember" abstract="true" name="ThreePointThreeSevenFiveSeniorNotesDueTwentyThirtyMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="wlk_ThreePointFiveZeroPercentSeniorNotesDueTwentyThirtyTwoMember" abstract="true" name="ThreePointFiveZeroPercentSeniorNotesDueTwentyThirtyTwoMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="wlk_A5.55SeniorNotesDueNovember2035Member" abstract="true" name="A5.55SeniorNotesDueNovember2035Member" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="wlk_A2875SeniorNotesDue2041Member" abstract="true" name="A2875SeniorNotesDue2041Member" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="wlk_FivePercentSeniorNotesDueTwentyFortySixMember" abstract="true" name="FivePercentSeniorNotesDueTwentyFortySixMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="wlk_FourPointThreeSevenFivePercentSeniorNotesDueTwentyFortySevenMember" abstract="true" name="FourPointThreeSevenFivePercentSeniorNotesDueTwentyFortySevenMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="wlk_ThreePointOneTwoFivePercentSeniorNotesDueTwentyFiftyOneMember" abstract="true" name="ThreePointOneTwoFivePercentSeniorNotesDueTwentyFiftyOneMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="wlk_A6.375SeniorNotesDueNovember2055Member" abstract="true" name="A6.375SeniorNotesDueNovember2055Member" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="wlk_ThreePointThreeSevenFivePercentSeniorNotesDueTwentySixtyOneMember" abstract="true" name="ThreePointThreeSevenFivePercentSeniorNotesDueTwentySixtyOneMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="wlk_TermLoanDueTwentyTwentySixMember" abstract="true" name="TermLoanDueTwentyTwentySixMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="wlk_ACIRevolverLoanMember" abstract="true" name="ACIRevolverLoanMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="wlk_CreditAgreementMember" abstract="true" name="CreditAgreementMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="wlk_NewCreditAgreementMember" abstract="true" name="NewCreditAgreementMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="wlk_SwinglineLoanMember" abstract="true" name="SwinglineLoanMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="wlk_AlternateBaseRateMember" abstract="true" name="AlternateBaseRateMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="wlk_LineOfCreditFacilityPermittedIncrease" abstract="false" name="LineOfCreditFacilityPermittedIncrease" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="wlk_NetIncomeLossAvailableToCommonStockholders" abstract="false" name="NetIncomeLossAvailableToCommonStockholders" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="wlk_LACCLLCMember" abstract="true" name="LACCLLCMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="wlk_EquityMethodInvestmentsActivityRollForward" abstract="true" name="EquityMethodInvestmentsActivityRollForward" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:stringItemType"/>
  <xs:element id="wlk_PernisFacilityClosureMember" abstract="true" name="PernisFacilityClosureMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="wlk_ChlorovinylsAndStyreneFacilityClosureMember" abstract="true" name="ChlorovinylsAndStyreneFacilityClosureMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="wlk_AssetRetirementObligationsMember" abstract="true" name="AssetRetirementObligationsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="wlk_InventoryWriteDownMember" abstract="true" name="InventoryWriteDownMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="wlk_AcceleratedDepreciationAndAmortizationMember" abstract="true" name="AcceleratedDepreciationAndAmortizationMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="wlk_DeferredTurnaroundCostsNet" abstract="false" name="DeferredTurnaroundCostsNet" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="wlk_AccruedRebatesCurrent" abstract="false" name="AccruedRebatesCurrent" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="wlk_ContractWithCustomerLiabilityRollForward" abstract="true" name="ContractWithCustomerLiabilityRollForward" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:stringItemType"/>
  <xs:element id="wlk_ContractWithCustomerLiabilityIncreaseForCashReceived" abstract="false" name="ContractWithCustomerLiabilityIncreaseForCashReceived" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="wlk_ContractWithCustomerLiabilityPaymentAdvance" abstract="false" name="ContractWithCustomerLiabilityPaymentAdvance" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="wlk_OtherPlantShutdownCostsMember" abstract="true" name="OtherPlantShutdownCostsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="wlk_CausticSodaAntitrustProceedingsMember" abstract="true" name="CausticSodaAntitrustProceedingsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="wlk_EthyleneAntitrustLitigationProceedingsMember" abstract="true" name="EthyleneAntitrustLitigationProceedingsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="wlk_PVCPipeAntitrustMember" abstract="true" name="PVCPipeAntitrustMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="wlk_BrazilianContractualIndemnificationLawsuitMember" abstract="true" name="BrazilianContractualIndemnificationLawsuitMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="wlk_CalvertCityProceedingsMember" abstract="true" name="CalvertCityProceedingsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="wlk_SulphurBrineDomeMember" abstract="true" name="SulphurBrineDomeMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="wlk_LitigationPlaintiffsAxis" abstract="true" name="LitigationPlaintiffsAxis" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrldt:dimensionItem" type="xbrli:stringItemType"/>
  <xs:element id="wlk_LitigationPlaintiffsDomain" abstract="true" name="LitigationPlaintiffsDomain" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="wlk_DirectPurchasersMember" abstract="true" name="DirectPurchasersMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="wlk_IndirectPurchasersMember" abstract="true" name="IndirectPurchasersMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="wlk_LitigationSettlementLegalFeeAndProceduralFinePercentage" abstract="false" name="LitigationSettlementLegalFeeAndProceduralFinePercentage" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:percentItemType"/>
  <xs:element id="wlk_PerformanceMaterialsMember" abstract="true" name="PerformanceMaterialsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="wlk_EssentialMaterialsMember" abstract="true" name="EssentialMaterialsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="wlk_HousingProductsMember" abstract="true" name="HousingProductsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="wlk_InfrastructureProductsMember" abstract="true" name="InfrastructureProductsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="wlk_RawMaterialEnergyAndManufacturingCosts" abstract="false" name="RawMaterialEnergyAndManufacturingCosts" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="wlk_DepreciationAndAmortizationSegmentExpenses" abstract="false" name="DepreciationAndAmortizationSegmentExpenses" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="wlk_SellingGeneralAndAdministrativeExpenses" abstract="false" name="SellingGeneralAndAdministrativeExpenses" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="wlk_DepreciationAndAmortizationSGA" abstract="false" name="DepreciationAndAmortizationSGA" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="wlk_RestructuringTransactionAndIntegrationRelatedCosts" abstract="false" name="RestructuringTransactionAndIntegrationRelatedCosts" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="wlk_TotalSellingGeneralAndAdministrativeExpenses" abstract="false" name="TotalSellingGeneralAndAdministrativeExpenses" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="wlk_WestlakeChemicalOpCoLPMember" abstract="true" name="WestlakeChemicalOpCoLPMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="wlk_WestlakeChemicalPartnersLPMember" abstract="true" name="WestlakeChemicalPartnersLPMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="wlk_PartnersUnitsMaximumAggregateOfferingAmountATM" abstract="false" name="PartnersUnitsMaximumAggregateOfferingAmountATM" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
</xs:schema>
