-----BEGIN PRIVACY-ENHANCED MESSAGE-----
Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
Originator-Key-Asymmetric:
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 TWSM7vrzLADbmYQaionwg5sDW3P6oaM5D3tdezXMm7z1T+B+twIDAQAB
MIC-Info: RSA-MD5,RSA,
 M5vJZzSaCY1oEb0vkFQjSNIf127E8mC6P4QKBMtxXKZYLv3xpFXLO87qGWdtzcRb
 KKu13X/bdc2SDSoDn+cm/w==

<SEC-DOCUMENT>0001179110-10-013486.txt : 20100903
<SEC-HEADER>0001179110-10-013486.hdr.sgml : 20100903
<ACCEPTANCE-DATETIME>20100903145123
ACCESSION NUMBER:		0001179110-10-013486
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20100901
FILED AS OF DATE:		20100903
DATE AS OF CHANGE:		20100903

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Brooks Lynn A
		CENTRAL INDEX KEY:			0001399307

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-10716
		FILM NUMBER:		101057444

	MAIL ADDRESS:	
		STREET 1:		500 W 7TH STREET
		CITY:			AUBURN
		STATE:			IN
		ZIP:			46706

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			TRIMAS CORP
		CENTRAL INDEX KEY:			0000842633
		STANDARD INDUSTRIAL CLASSIFICATION:	METAL FORGING & STAMPINGS [3460]
		IRS NUMBER:				382687639
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		39400 WOODWARD AVENUE, SUITE 130
		CITY:			BLOOMFIELD HILLS
		STATE:			MI
		ZIP:			48304
		BUSINESS PHONE:		2486315400

	MAIL ADDRESS:	
		STREET 1:		39400 WOODWARD AVENUE, SUITE 130
		CITY:			BLOOMFIELD HILLS
		STATE:			MI
		ZIP:			48304
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>edgar.xml
<DESCRIPTION>FORM 4 -
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0303</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2010-09-01</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000842633</issuerCik>
        <issuerName>TRIMAS CORP</issuerName>
        <issuerTradingSymbol>TRS</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001399307</rptOwnerCik>
            <rptOwnerName>Brooks Lynn A</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>500 W. 7TH STREET</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>AUBURN</rptOwnerCity>
            <rptOwnerState>IN</rptOwnerState>
            <rptOwnerZipCode>46706</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>President - Packaging</officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2010-09-01</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>F</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>846</value>
                    <footnoteId id="F1"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>14.01</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>42772</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable></derivativeTable>

    <footnotes>
        <footnote id="F1">Shares used to satisfy tax withholding obligation.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>/s/ Paula Reno attorney-in-fact</signatureName>
        <signatureDate>2010-09-03</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
-----END PRIVACY-ENHANCED MESSAGE-----