<SEC-DOCUMENT>0001628280-16-018754.txt : 20160808
<SEC-HEADER>0001628280-16-018754.hdr.sgml : 20160808
<ACCEPTANCE-DATETIME>20160808202142
ACCESSION NUMBER:		0001628280-16-018754
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20160804
FILED AS OF DATE:		20160808
DATE AS OF CHANGE:		20160808

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			KLA TENCOR CORP
		CENTRAL INDEX KEY:			0000319201
		STANDARD INDUSTRIAL CLASSIFICATION:	OPTICAL INSTRUMENTS & LENSES [3827]
		IRS NUMBER:				042564110
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			0630

	BUSINESS ADDRESS:	
		STREET 1:		ONE TECHNOLOGY DRIVE
		CITY:			MILPITAS
		STATE:			CA
		ZIP:			95035
		BUSINESS PHONE:		4088756000

	MAIL ADDRESS:	
		STREET 1:		ONE TECHNOLOGY DRIVE
		CITY:			MILPITAS
		STATE:			CA
		ZIP:			95035

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	KLA INSTRUMENTS CORP
		DATE OF NAME CHANGE:	19920703

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Little Teri A.
		CENTRAL INDEX KEY:			0001656471

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-09992
		FILM NUMBER:		161815798

	MAIL ADDRESS:	
		STREET 1:		ONE TECHNOLOGY DRIVE
		CITY:			MILPITAS
		STATE:			CA
		ZIP:			95035
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>wf-form4_147070208996827.xml
<DESCRIPTION>FORM 4
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2016-08-04</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000319201</issuerCik>
        <issuerName>KLA TENCOR CORP</issuerName>
        <issuerTradingSymbol>KLAC</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001656471</rptOwnerCik>
            <rptOwnerName>Little Teri A.</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>ONE TECHNOLOGY DRIVE</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>MILPITAS</rptOwnerCity>
            <rptOwnerState>CA</rptOwnerState>
            <rptOwnerZipCode>95035</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>SVP, GC and Secretary</officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock - Restricted Stock Unit</value>
            </securityTitle>
            <transactionDate>
                <value>2016-08-04</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>7600</value>
                    <footnoteId id="F1"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>20778</value>
                    <footnoteId id="F2"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>6998</value>
                    <footnoteId id="F3"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
    </nonDerivativeTable>

    <derivativeTable></derivativeTable>

    <footnotes>
        <footnote id="F1">Represents a grant of RSUs subject only to service-vesting requirements.  The Reporting Person will vest twenty-five percent (25%) of the RSUs on the one-year anniversary of the grant date (August 4, 2017) and an additional twenty-five percent (25%) on each annual anniversary of the grant date thereafter through August 4, 2020, in each case subject to the Reporting Person continuing as a service provider to KLA-Tencor through the applicable vesting date.  Shares of common stock will be issued as the RSUs vest.</footnote>
        <footnote id="F2">Does not include performance-based RSUs, if any, held by the Reporting Person for which an assessment has not yet been made regarding the achievement of the applicable performance goals.  Any such holdings will be reported on a Form 4 within two business days of the date such assessment is made.</footnote>
        <footnote id="F3">Includes 138 shares acquired on December 31, 2015 and 278 shares on June 30, 2016 by the Reporting Person under the KLA-Tencor Employee Stock Purchase Plan.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>Teri A. Little</signatureName>
        <signatureDate>2016-08-08</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
