<SEC-DOCUMENT>0000824142-14-000102.txt : 20141106
<SEC-HEADER>0000824142-14-000102.hdr.sgml : 20141106
<ACCEPTANCE-DATETIME>20141106095340
ACCESSION NUMBER:		0000824142-14-000102
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20141104
FILED AS OF DATE:		20141106
DATE AS OF CHANGE:		20141106

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			AAON INC
		CENTRAL INDEX KEY:			0000824142
		STANDARD INDUSTRIAL CLASSIFICATION:	AIR COND & WARM AIR HEATING EQUIP & COMM & INDL REFRIG EQUIP [3585]
		IRS NUMBER:				870448736
		STATE OF INCORPORATION:			NV
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		2425 SOUTH YUKON
		CITY:			TULSA
		STATE:			OK
		ZIP:			74107
		BUSINESS PHONE:		9185832266

	MAIL ADDRESS:	
		STREET 1:		2425 SOUTH YUKON
		CITY:			TULSA
		STATE:			OK
		ZIP:			74107

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	DIAMOND HEAD RESOURCES INC
		DATE OF NAME CHANGE:	19900808

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			ASBJORNSON NORMAN H
		CENTRAL INDEX KEY:			0000903063

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-18953
		FILM NUMBER:		141199167

	MAIL ADDRESS:	
		STREET 1:		AAON INC
		STREET 2:		2425 SOUTH YUKON
		CITY:			TULSA
		STATE:			OK
		ZIP:			74107
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>wf-form4_141528561021213.xml
<DESCRIPTION>FORM 4
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2014-11-04</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000824142</issuerCik>
        <issuerName>AAON INC</issuerName>
        <issuerTradingSymbol>AAON</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0000903063</rptOwnerCik>
            <rptOwnerName>ASBJORNSON NORMAN H</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>AAON INC</rptOwnerStreet1>
            <rptOwnerStreet2>2425 SOUTH YUKON</rptOwnerStreet2>
            <rptOwnerCity>TULSA</rptOwnerCity>
            <rptOwnerState>OK</rptOwnerState>
            <rptOwnerZipCode>74107</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>President</officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock, par value $.004</value>
            </securityTitle>
            <transactionDate>
                <value>2014-11-04</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>G</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>4170</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>20.13</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>10278147</value>
                    <footnoteId id="F1"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock, par value $.004</value>
            </securityTitle>
            <transactionDate>
                <value>2014-11-04</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>G</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>1390</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>20.13</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>550314</value>
                    <footnoteId id="F1"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>Trustee of trusts</value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock, par value $.004</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>474655</value>
                    <footnoteId id="F1"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>Private Foundation</value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
    </nonDerivativeTable>

    <derivativeTable></derivativeTable>

    <footnotes>
        <footnote id="F1">Adjusted to reflect a 3 for 2 stock split on July 16, 2014 effected pursuant to a 50% stock dividend.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>Norman H. Asbjornson</signatureName>
        <signatureDate>2014-11-06</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
