<SEC-DOCUMENT>0001520367-20-000006.txt : 20200609
<SEC-HEADER>0001520367-20-000006.hdr.sgml : 20200609
<ACCEPTANCE-DATETIME>20200609160948
ACCESSION NUMBER:		0001520367-20-000006
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20200605
FILED AS OF DATE:		20200609
DATE AS OF CHANGE:		20200609

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Burns Robert Nicholas
		CENTRAL INDEX KEY:			0001520367

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-32598
		FILM NUMBER:		20951938

	MAIL ADDRESS:	
		STREET 1:		C/O ENTEGRIS, INC.
		STREET 2:		129 CONCORD ROAD
		CITY:			BILLERICA
		STATE:			MA
		ZIP:			01821

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			ENTEGRIS INC
		CENTRAL INDEX KEY:			0001101302
		STANDARD INDUSTRIAL CLASSIFICATION:	PLASTICS PRODUCTS, NEC [3089]
		IRS NUMBER:				411941551
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		129 CONCORD ROAD
		CITY:			BILLERICA
		STATE:			MA
		ZIP:			01821
		BUSINESS PHONE:		9784366500

	MAIL ADDRESS:	
		STREET 1:		129 CONCORD ROAD
		CITY:			BILLERICA
		STATE:			MA
		ZIP:			01821
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>wf-form4_159173337097041.xml
<DESCRIPTION>FORM 4
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2020-06-05</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001101302</issuerCik>
        <issuerName>ENTEGRIS INC</issuerName>
        <issuerTradingSymbol>ENTG</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001520367</rptOwnerCik>
            <rptOwnerName>Burns Robert Nicholas</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O ENTEGRIS, INC.</rptOwnerStreet1>
            <rptOwnerStreet2>129 CONCORD ROAD</rptOwnerStreet2>
            <rptOwnerCity>BILLERICA</rptOwnerCity>
            <rptOwnerState>MA</rptOwnerState>
            <rptOwnerZipCode>01821</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2020-06-05</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>3120</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>64.301</value>
                    <footnoteId id="F1"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>42808</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable></derivativeTable>

    <footnotes>
        <footnote id="F1">The price reported in column 4 is a weighted average price reported in reliance on a letter from the Office of Chief Counsel, Securities and Exchange Commission's Division of Corporate Finance to the Society of Corporate Governance Professionals dated June 25, 2008. These shares were sold in multiple transactions at prices ranging from $64.25 to $64.33, inclusive. The reporting person undertakes to provide Entegris, Inc., any shareholder of Entegris, Inc., or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the ranges set forth in this footnote.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>/s/ Joseph Colella, Attorney-In-Fact for R. Nicholas Burns</signatureName>
        <signatureDate>2020-06-09</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
