<SEC-DOCUMENT>0001628280-23-028643.txt : 20230809
<SEC-HEADER>0001628280-23-028643.hdr.sgml : 20230809
<ACCEPTANCE-DATETIME>20230809170306
ACCESSION NUMBER:		0001628280-23-028643
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20230807
FILED AS OF DATE:		20230809
DATE AS OF CHANGE:		20230809

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			SLESSOR MIKE
		CENTRAL INDEX KEY:			0001590177

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-50307
		FILM NUMBER:		231156122

	MAIL ADDRESS:	
		STREET 1:		7005 SOUTHFRONT ROAD
		CITY:			LIVERMORE
		STATE:			CA
		ZIP:			94551

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			FORMFACTOR INC
		CENTRAL INDEX KEY:			0001039399
		STANDARD INDUSTRIAL CLASSIFICATION:	SEMICONDUCTORS & RELATED DEVICES [3674]
		IRS NUMBER:				133711155
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1230

	BUSINESS ADDRESS:	
		STREET 1:		7005 SOUTHFRONT ROAD
		CITY:			LIVERMORE
		STATE:			CA
		ZIP:			94551
		BUSINESS PHONE:		9252904000

	MAIL ADDRESS:	
		STREET 1:		7005 SOUTHFRONT ROAD
		CITY:			LIVERMORE
		STATE:			CA
		ZIP:			94551
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>wf-form4_169161497058524.xml
<DESCRIPTION>FORM 4
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0508</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2023-08-07</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001039399</issuerCik>
        <issuerName>FORMFACTOR INC</issuerName>
        <issuerTradingSymbol>FORM</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001590177</rptOwnerCik>
            <rptOwnerName>SLESSOR MIKE</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>7005 SOUTHFRONT ROAD</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>LIVERMORE</rptOwnerCity>
            <rptOwnerState>CA</rptOwnerState>
            <rptOwnerZipCode>94551</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>CEO</officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <aff10b5One>0</aff10b5One>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2023-08-07</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>70896</value>
                    <footnoteId id="F1"/>
                    <footnoteId id="F2"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>563136</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable></derivativeTable>

    <footnotes>
        <footnote id="F1">Restricted stock units (&quot;RSUs&quot;) vest quarterly over a three-year period beginning on the grant date.</footnote>
        <footnote id="F2">If the reporting person's employment is terminated for any reason before an applicable vesting date, all RSUs that have not yet vested shall be forfeited without consideration, except as provided in the change of control severance agreement and any other agreements regarding equity vesting and exercisability between the reporting person and Issuer, which agreements or form agreements are filed with the SEC.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>By: /s/ Stan Finkelstein, Attorney-in-Fact for Mike Slessor</signatureName>
        <signatureDate>2023-08-09</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
