<SEC-DOCUMENT>0001013857-21-000247.txt : 20211102
<SEC-HEADER>0001013857-21-000247.hdr.sgml : 20211102
<ACCEPTANCE-DATETIME>20211102171308
ACCESSION NUMBER:		0001013857-21-000247
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20211101
FILED AS OF DATE:		20211102
DATE AS OF CHANGE:		20211102

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			STILLWELL KENNETH
		CENTRAL INDEX KEY:			0001680115

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-11859
		FILM NUMBER:		211372477

	MAIL ADDRESS:	
		STREET 1:		ONE ROGERS STREET
		CITY:			CAMBRDIGE
		STATE:			MA
		ZIP:			02142

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			PEGASYSTEMS INC
		CENTRAL INDEX KEY:			0001013857
		STANDARD INDUSTRIAL CLASSIFICATION:	SERVICES-COMPUTER PROCESSING & DATA PREPARATION [7374]
		IRS NUMBER:				042787865
		STATE OF INCORPORATION:			MA
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		ONE MAIN STREET
		CITY:			CAMBRIDGE
		STATE:			MA
		ZIP:			02142-1531
		BUSINESS PHONE:		6173749600

	MAIL ADDRESS:	
		STREET 1:		ONE MAIN STREET
		CITY:			CAMBRIDGE
		STATE:			MA
		ZIP:			02142-1531
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>wf-form4_163588754713922.xml
<DESCRIPTION>FORM 4
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2021-11-01</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001013857</issuerCik>
        <issuerName>PEGASYSTEMS INC</issuerName>
        <issuerTradingSymbol>PEGA</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001680115</rptOwnerCik>
            <rptOwnerName>STILLWELL KENNETH</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O PEGASYSTEMS INC.</rptOwnerStreet1>
            <rptOwnerStreet2>ONE MAIN STREET</rptOwnerStreet2>
            <rptOwnerCity>CAMBRIDGE</rptOwnerCity>
            <rptOwnerState>MA</rptOwnerState>
            <rptOwnerZipCode>02142</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>COO, CFO</officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common stock</value>
            </securityTitle>
            <transactionDate>
                <value>2021-11-01</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>1000</value>
                    <footnoteId id="F1"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>118.66</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>7826</value>
                    <footnoteId id="F2"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable></derivativeTable>

    <footnotes>
        <footnote id="F1">Sold pursuant to a pre-arranged stock trading plan under Rule 10b5-1 of the Securities Exchange Act of 1934, as amended.</footnote>
        <footnote id="F2">Does not include shares of common stock subject to unvested restricted stock units and/or options awards.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>/s/ Donald L. Lancaster, Attorney-in-Fact for Kenneth Stillwell</signatureName>
        <signatureDate>2021-11-02</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
