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Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
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MIC-Info: RSA-MD5,RSA,
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 1+d5VvTXzfXh1x7lAIE/VA==

<SEC-DOCUMENT>0001140361-06-004434.txt : 20060323
<SEC-HEADER>0001140361-06-004434.hdr.sgml : 20060323
<ACCEPTANCE-DATETIME>20060323161726
ACCESSION NUMBER:		0001140361-06-004434
CONFORMED SUBMISSION TYPE:	4/A
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20060320
FILED AS OF DATE:		20060323
DATE AS OF CHANGE:		20060323

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			WESTLAKE CHEMICAL CORP
		CENTRAL INDEX KEY:			0001262823
		STANDARD INDUSTRIAL CLASSIFICATION:	INDUSTRIAL ORGANIC CHEMICALS [2860]
		IRS NUMBER:				760346924

	MAIL ADDRESS:	
		STREET 1:		2801 POST OAK BLVD
		STREET 2:		SUITE 600
		CITY:			HOUSTON
		STATE:			TX
		ZIP:			77056

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Chao Albert
		CENTRAL INDEX KEY:			0001299403

	FILING VALUES:
		FORM TYPE:		4/A
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-32260
		FILM NUMBER:		06706339

	BUSINESS ADDRESS:	
		BUSINESS PHONE:		713-960-9111

	MAIL ADDRESS:	
		STREET 1:		2801 POST OAK BLVD. SUITE 600
		CITY:			HOUSTON
		STATE:			TX
		ZIP:			77056
</SEC-HEADER>
<DOCUMENT>
<TYPE>4/A
<SEQUENCE>1
<FILENAME>doc1.xml
<DESCRIPTION>FORM 4/A
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0202</schemaVersion>

    <documentType>4/A</documentType>

    <periodOfReport>2006-03-20</periodOfReport>

    <dateOfOriginalSubmission>2006-03-22</dateOfOriginalSubmission>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001262823</issuerCik>
        <issuerName>WESTLAKE CHEMICAL CORP</issuerName>
        <issuerTradingSymbol>WLK</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001299403</rptOwnerCik>
            <rptOwnerName>Chao Albert</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>2801 POST OAK BLVD.</rptOwnerStreet1>
            <rptOwnerStreet2>SUITE 600</rptOwnerStreet2>
            <rptOwnerCity>HOUSTON</rptOwnerCity>
            <rptOwnerState>TX</rptOwnerState>
            <rptOwnerZipCode>77056</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>President and CEO</officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
                <footnoteId id="F1"/>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>20000</value>
                    <footnoteId id="F1"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>By Mother</value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">This amended Form 4 is being filed solely to correct an Edgar system filing error that resulted in a prior holding being reported as if it were a new transaction (even though the date of the transaction was always clearly set forth as August 16, 2004).  The original transaction resulting in the holding was previously reported in a Form 4 timely filed by the reporting person on August 18, 2004 and therefore should not have been reported as a transaction in this Form 4.</footnote>
    </footnotes>

    <remarks>51,505,277 shares are held indirectly through TTWF LP, a Delaware limited partnership.  Two trusts for the benefit of members of the Chao family, including the reporting person, are the managers of TTWFGP LLC, a Delaware limited liability company that is the general partner of TTWF LP.  The limited partners of TTWF LP are five trusts principally for the benefit of members of the Chao family, including the reporting person, and two corporations owned, indirectly or directly, by certain of these trusts and by other entities owned by members of the Chao family, including the reporting person.  The reporting person shares investment and voting power with respect to the shares beneficially owned by TTWF LP.  The reporting person disclaims beneficial ownership of the shares except to the extent of his pecuniary interest therein.</remarks>

    <ownerSignature>
        <signatureName>Albert Chao  by Andrew Ralston, POA</signatureName>
        <signatureDate>2006-03-23</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
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