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Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
Originator-Key-Asymmetric:
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 TWSM7vrzLADbmYQaionwg5sDW3P6oaM5D3tdezXMm7z1T+B+twIDAQAB
MIC-Info: RSA-MD5,RSA,
 VWnNX/DalrI1DujNSb2TsOF26qfNJse/YyOLY/NIJ5i/ize/Vw8a+kf14jSRjFAZ
 kXhtaqmB4gecTMpi339WOA==

<SEC-DOCUMENT>0001140361-08-014577.txt : 20080606
<SEC-HEADER>0001140361-08-014577.hdr.sgml : 20080606
<ACCEPTANCE-DATETIME>20080606182029
ACCESSION NUMBER:		0001140361-08-014577
CONFORMED SUBMISSION TYPE:	3
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20080522
FILED AS OF DATE:		20080606
DATE AS OF CHANGE:		20080606

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			KNIGHT TRANSPORTATION INC
		CENTRAL INDEX KEY:			0000929452
		STANDARD INDUSTRIAL CLASSIFICATION:	TRUCKING (NO LOCAL) [4213]
		IRS NUMBER:				860649974
		STATE OF INCORPORATION:			AZ
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		5601 W BUCKEYE RD
		CITY:			PHOENIX
		STATE:			AZ
		ZIP:			85043
		BUSINESS PHONE:		6022692000

	MAIL ADDRESS:	
		STREET 1:		5601 W BUCKEYE RD
		CITY:			PHOENIX
		STATE:			AZ
		ZIP:			85043

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Ramsey William
		CENTRAL INDEX KEY:			0001437054

	FILING VALUES:
		FORM TYPE:		3
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-32396
		FILM NUMBER:		08886744

	BUSINESS ADDRESS:	
		BUSINESS PHONE:		6022692000

	MAIL ADDRESS:	
		STREET 1:		5601 WEST BUCKEYE ROAD
		CITY:			PHOENIX
		STATE:			AZ
		ZIP:			85043
</SEC-HEADER>
<DOCUMENT>
<TYPE>3
<SEQUENCE>1
<FILENAME>doc1.xml
<DESCRIPTION>FORM 3
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0202</schemaVersion>

    <documentType>3</documentType>

    <periodOfReport>2008-05-22</periodOfReport>

    <noSecuritiesOwned>0</noSecuritiesOwned>

    <issuer>
        <issuerCik>0000929452</issuerCik>
        <issuerName>KNIGHT TRANSPORTATION INC</issuerName>
        <issuerTradingSymbol>KNX</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001437054</rptOwnerCik>
            <rptOwnerName>Ramsey William</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>5601 WEST BUCKEYE ROAD</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>PHOENIX</rptOwnerCity>
            <rptOwnerState>AZ</rptOwnerState>
            <rptOwnerZipCode>85043</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>Senior Vice President</officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock, par value $0.01 per share</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>0</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
    </nonDerivativeTable>

    <derivativeTable>
        <derivativeHolding>
            <securityTitle>
                <value>Common Stock, par value $0.01 per share</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>2.85</value>
                <footnoteId id="F1"/>
            </conversionOrExercisePrice>
            <exerciseDate>
                <value>2008-06-06</value>
                <footnoteId id="F1"/>
            </exerciseDate>
            <expirationDate>
                <value>2010-10-12</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>1688</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeHolding>
        <derivativeHolding>
            <securityTitle>
                <value>Common Stock, par value $0.01 per share</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>4.89</value>
                <footnoteId id="F2"/>
            </conversionOrExercisePrice>
            <exerciseDate>
                <value>2008-06-06</value>
                <footnoteId id="F2"/>
            </exerciseDate>
            <expirationDate>
                <value>2011-09-17</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>2250</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeHolding>
        <derivativeHolding>
            <securityTitle>
                <value>Common Stock, par value $0.01 per share</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>8.44</value>
                <footnoteId id="F3"/>
            </conversionOrExercisePrice>
            <exerciseDate>
                <value>2008-06-06</value>
                <footnoteId id="F3"/>
            </exerciseDate>
            <expirationDate>
                <value>2012-06-04</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>1650</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeHolding>
        <derivativeHolding>
            <securityTitle>
                <value>Common Stock, par value $0.01 per share</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>11.44</value>
                <footnoteId id="F4"/>
            </conversionOrExercisePrice>
            <exerciseDate>
                <value>2008-06-06</value>
                <footnoteId id="F4"/>
            </exerciseDate>
            <expirationDate>
                <value>2013-08-06</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>2813</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeHolding>
        <derivativeHolding>
            <securityTitle>
                <value>Common Stock, par value $0.01 per share</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>10.54</value>
                <footnoteId id="F5"/>
            </conversionOrExercisePrice>
            <exerciseDate>
                <value>2008-06-06</value>
                <footnoteId id="F5"/>
            </exerciseDate>
            <expirationDate>
                <value>2014-03-18</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>3938</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeHolding>
        <derivativeHolding>
            <securityTitle>
                <value>Common Stock, par value $0.01 per share</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>14.48</value>
                <footnoteId id="F6"/>
            </conversionOrExercisePrice>
            <exerciseDate>
                <value>2008-04-26</value>
                <footnoteId id="F6"/>
            </exerciseDate>
            <expirationDate>
                <value>2015-04-25</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>4125</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeHolding>
        <derivativeHolding>
            <securityTitle>
                <value>Common Stock, par value $0.01 per share</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>18.75</value>
                <footnoteId id="F7"/>
            </conversionOrExercisePrice>
            <exerciseDate>
                <value>2009-05-18</value>
                <footnoteId id="F7"/>
            </exerciseDate>
            <expirationDate>
                <value>2016-05-17</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>4000</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeHolding>
        <derivativeHolding>
            <securityTitle>
                <value>Common Stock, par value $0.01 per share</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>18.77</value>
                <footnoteId id="F8"/>
            </conversionOrExercisePrice>
            <exerciseDate>
                <value>2009-05-19</value>
                <footnoteId id="F8"/>
            </exerciseDate>
            <expirationDate>
                <value>2016-05-18</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>1000</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeHolding>
        <derivativeHolding>
            <securityTitle>
                <value>Common Stock, par value $0.01 per share</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>18.20</value>
                <footnoteId id="F9"/>
            </conversionOrExercisePrice>
            <exerciseDate>
                <value>2010-05-25</value>
                <footnoteId id="F9"/>
            </exerciseDate>
            <expirationDate>
                <value>2017-05-24</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>5500</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeHolding>
        <derivativeHolding>
            <securityTitle>
                <value>Common Stock, par value $0.01 per share</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>14.79</value>
                <footnoteId id="F10"/>
            </conversionOrExercisePrice>
            <exerciseDate>
                <value>2011-02-28</value>
                <footnoteId id="F10"/>
            </exerciseDate>
            <expirationDate>
                <value>2018-02-27</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>10000</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeHolding>
        <derivativeHolding>
            <securityTitle>
                <value>Common Stock, par value $0.01 per share</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>17.29</value>
                <footnoteId id="F11"/>
            </conversionOrExercisePrice>
            <exerciseDate>
                <value>2011-05-22</value>
                <footnoteId id="F11"/>
            </exerciseDate>
            <expirationDate>
                <value>2018-05-21</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>7500</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeHolding>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">Mr. Ramsey was granted an option to purchase 5,063 shares of stock at the grant price of $2.85 per share on October 13, 2000 of which 3,375 have been exercised and 1,688 are vested and exercisable.</footnote>
        <footnote id="F2">Mr. Ramsey was granted an option to purchase 3,375 shares of stock at the grant price of $4.8889 per share on September 18, 2001 of which 1,125 have been exercised and 2,250 are vested and exercisable.</footnote>
        <footnote id="F3">Mr. Ramsey was granted an option to purchase 2,475 shares of stock at the grant price of $8.4445 per share on June 5, 2002 of which 825 have been exercised and 1,650 are vested and exercisable.</footnote>
        <footnote id="F4">Mr. Ramsey was granted an option to purchase 2,813 shares of stock at the grant price of $11.4356 per share on August 7, 2003 of which 1,125 are currently vested and the remaining shares shall vest as follows:  562 shares on August 7, 2008 and 563 shares each on August 7, 2009 and 2010.</footnote>
        <footnote id="F5">Mr. Ramsey was granted an option to purchase 3,938 shares of stock at the grant price of $10.5378 per share on March 19, 2004 of which 1,575 are currently vested and the remaining shares shall vest as follows:  787 shares on March 19, 2009 and 788 shares each on March 19, 2010 and March 19, 2011.</footnote>
        <footnote id="F6">Mr. Ramsey was granted an option to purchase 4,125 shares of stock at the grant price of $14.48 per share on April 26, 2005 of which 825 are currently vested and the remaining shares shall vest as follows:  825 shares annually beginning on April 26, 2009, until fully vested.</footnote>
        <footnote id="F7">Mr. Ramsey was granted an option to purchase 4,000 shares of stock at the grant price of $18.75 per share on May 18, 2006, to vest as follows:  800 shares annually beginning on May 18, 2009, until fully vested.</footnote>
        <footnote id="F8">Mr. Ramsey was granted an option to purchase 1,000 shares of stock at the grant price of $18.77 per share on May 19, 2006, to vest as follows:  200 shares annually beginning on May 19, 2009, until fully vested.</footnote>
        <footnote id="F9">Mr. Ramsey was granted an option to purchase 5,500 shares of stock at the grant price of $18.20 per share on May 25, 2007, to vest as follows:  1,100 shares annually beginning on May 25, 2010, until fully vested.</footnote>
        <footnote id="F10">Mr. Ramsey was granted an option to purchase 10,000 shares of stock at the grant price of $14.79 per share on February 29, 2008, to vest as follows:  2,000 shares annually beginning on February 28, 2010, until fully vested.</footnote>
        <footnote id="F11">Mr. Ramsey was granted an option to purchase 7,500 shares at the grant price of $17.29 per share to vest as follows:  20% each year beginning on May 22, 2011, until fully vested.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>/S/ William Ramsey</signatureName>
        <signatureDate>2008-06-06</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
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