<SEC-DOCUMENT>0000056978-19-000117.txt : 20191104
<SEC-HEADER>0000056978-19-000117.hdr.sgml : 20191104
<ACCEPTANCE-DATETIME>20191104103153
ACCESSION NUMBER:		0000056978-19-000117
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20191031
FILED AS OF DATE:		20191104
DATE AS OF CHANGE:		20191104

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Sood Deepak
		CENTRAL INDEX KEY:			0001561373

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-00121
		FILM NUMBER:		191188524

	MAIL ADDRESS:	
		STREET 1:		23A, SERANGOON NORTH AVENUE 5 #01-01
		CITY:			SINGAPORE
		STATE:			U0
		ZIP:			554369

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			KULICKE & SOFFA INDUSTRIES INC
		CENTRAL INDEX KEY:			0000056978
		STANDARD INDUSTRIAL CLASSIFICATION:	SEMICONDUCTORS & RELATED DEVICES [3674]
		IRS NUMBER:				231498399
		STATE OF INCORPORATION:			PA
		FISCAL YEAR END:			0928

	BUSINESS ADDRESS:	
		STREET 1:		23A SERANGOON NORTH AVENUE 5, #01-01
		CITY:			SINGAPORE
		STATE:			U0
		ZIP:			554369
		BUSINESS PHONE:		2157846000

	MAIL ADDRESS:	
		STREET 1:		23A SERANGOON NORTH AVENUE 5, #01-01
		CITY:			SINGAPORE
		STATE:			U0
		ZIP:			554369
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>wf-form4_157288149864409.xml
<DESCRIPTION>FORM 4
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2019-10-31</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000056978</issuerCik>
        <issuerName>KULICKE &amp; SOFFA INDUSTRIES INC</issuerName>
        <issuerTradingSymbol>KLIC</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001561373</rptOwnerCik>
            <rptOwnerName>Sood Deepak</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>23A SERANGOON NORTH AVENUE 5</rptOwnerStreet1>
            <rptOwnerStreet2>#01-01</rptOwnerStreet2>
            <rptOwnerCity>SINGAPORE</rptOwnerCity>
            <rptOwnerState></rptOwnerState>
            <rptOwnerZipCode>U0 554369</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>Vice President</officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2019-10-31</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>M</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>19139</value>
                    <footnoteId id="F1"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>149595</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Performance Share Units</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>0.0</value>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2019-10-31</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>M</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>19139</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <footnoteId id="F1"/>
            </exerciseDate>
            <expirationDate>
                <footnoteId id="F1"/>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>19139.0</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>0</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">Performance Share Units (PSUs) awarded October 31, 2016 had its performance results certified, and then shares vested, on October 31, 2019 at 141% achievement based on total shareholder return (TSR) relative to a peer group.  The peer group consisted of companies of the GICS 45301020 (Semiconductors) not including companies traded on the Pink Sheets LLC Exchange as of the beginning of Performance Period, with relative TSR measured over a three year measurement period.  Each PSU is convertible into one share of Kulicke and Soffa Industries Inc. common stock.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>Susan L. Waters, Attorney-in-Fact for Deepak Sood</signatureName>
        <signatureDate>2019-11-04</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
