SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549

                                    FORM 8-K
                                 CURRENT REPORT
                       Pursuant to Section 13 or 15(d) of
                       the Securities Exchange Act of 1934

                Date of Report (Date of earliest event reported):
                                  May 12, 2003

                           KNIGHT TRANSPORTATION, INC.
             (Exact name of registrant as specified in its charter)


          Arizona                    000-24946                   86-0649974
(STATE OR OTHER JURISDICTION        (COMMISSION               (I.R.S. EMPLOYER
     OF INCORPORATION)              FILE NUMBER)             IDENTIFICATION NO.)


                  5601 W. BUCKEYE ROAD, PHOENIX, ARIZONA 85043
              (ADDRESS OF PRINCIPAL EXECUTIVE OFFICES) (ZIP CODE)


               REGISTRANT'S TELEPHONE NUMBER, INCLUDING AREA CODE:
                                 (602) 269-2000


                                 NOT APPLICABLE
          (FORMER NAME OR FORMER ADDRESS, IF CHANGED SINCE LAST REPORT)

ITEM 1. CHANGES IN CONTROL OF REGISTRANT

     Not applicable.

ITEM 2. ACQUISITION OR DISPOSITION OF ASSETS

     Not applicable.

ITEM 3. BANKRUPTCY OR RECEIVERSHIP

     Not applicable.

ITEM 4. CHANGES IN REGISTRANT'S CERTIFYING ACCOUNTANT

     Not applicable.

ITEM 5. OTHER EVENTS AND REGULATION FD DISCLOSURE

     Not applicable.

ITEM 6. RESIGNATIONS OF REGISTRANT'S DIRECTORS

     Not applicable.

ITEM 7. FINANCIAL STATEMENTS AND EXHIBITS

     (c) Exhibits.

     EXHIBIT
     NUMBER      EXHIBIT TITLE
     ------      -------------

      99.1     Certification  pursuant  to 18 U.S.C.  Section  1350,  as adopted
               pursuant to Section  906 of the  Sarbanes-Oxley  Act of 2002,  by
               Kevin P. Knight, the Company's Chief Executive Officer.

      99.2     Certification  pursuant  to 18 U.S.C.  Section  1350,  as adopted
               pursuant to Section  906 of the  Sarbanes-Oxley  Act of 2002,  by
               Timothy M. Kohl, the Company's Chief Financial Officer.

ITEM 8. CHANGE IN FISCAL YEAR

     Not applicable.

ITEM 9. REGULATION FD DISCLOSURE

     Concurrently with the filing of the Knight Transportation, Inc., an Arizona
corporation  (the  "Company"),  Form 10-Q for the quarter  ended March 31, 2003,
Kevin P. Knight,  the  Company's  President  and Chief  Executive  Officer,  and
Timothy M. Kohl, the Company's Chief Financial Officer,  provided to the SEC the
certifications  required pursuant to 18 U.S.C. Section 1350, as adopted pursuant
to Section 906 of the Sarbanes-Oxley Act of 2002. Copies of such  certifications
are attached hereto as exhibits 99.1 and 99.2, respectively.

     The  certifications  attached  hereto are being furnished to the Securities
and Exchange Commission solely pursuant to Section 906 of the Sarbanes-Oxley Act
of 2002,  and are not  being  filed as part of the  Company's  Form 10-Q for the
quarter  ended  March  31,  2003  or  as a  separate  disclosure  document.  The
information  included in this Current Report on Form 8-K (including the exhibits
hereto) is  furnished  pursuant to Item 9, and shall not be deemed to be "filed"
for purposes of Section 18 of the  Securities  Exchange Act of 1934, as amended,
or  otherwise  subject to the  liabilities  of that  Section or  Sections 11 and
12(a)(2) of the  Securities  Act of 1933,  as  amended.  The  furnishing  of the
information in this Current Report is not intended to, and does not,  constitute
a  representation  that such furnishing is required by Regulation FD or that the
information this Current Report contains is material to investors.

                                    SIGNATURE

     Pursuant to the  requirements  of the Securities  Exchange Act of 1934, the
registrant  has duly  caused  this  report  to be  signed  on its  behalf by the
undersigned hereunto duly authorized.


                                     KNIGHT TRANSPORTATION, INC.


Date: May 12, 2003                   /s/ Timothy M. Kohl
                                     -------------------------------------------
                                     Timothy M. Kohl
                                     Executive Vice President, Secretary, and
                                     Chief Financial Officer

                                  EXHIBIT INDEX

99.1   Certification  pursuant to 18 U.S.C. Section 1350, as adopted pursuant to
       Section 906 of the  Sarbanes-Oxley  Act of 2002, by Kevin P. Knight,  the
       Company's Chief Executive Officer.

99.2   Certification  pursuant to 18 U.S.C. Section 1350, as adopted pursuant to
       Section 906 of the  Sarbanes-Oxley  Act of 2002, by Timothy M. Kohl,  the
       Company's Chief Financial Officer.