

                                      5.0





                                December 1, 1999



BOK Financial Corporation
Bank of Oklahoma Tower
P.O. Box 2300
Tulsa, OK  74192


          Re:  BOK Financial Corporation SEC Registration Statement on Form S-8:
               BOK Financial  Corporation  (Trading  Symbol  "BOKF"):  1,800,000
               Shares  of BOKF  Common  Stock to be Issued  Pursuant  to the BOK
               Financial Corporation 2000 Stock Option Plan.


Ladies and Gentleman:

     I have acted as counsel to BOK Financial Corporation ("BOKF") in connection
with BOKF's Registration  Statement on Form S-8 being filed on or about December
1, 1999 with the Securities and Exchange  Commission which respect to the shares
of Common Stock (the "Common  Stock"),  $0.00006 par value, of BOKF,  authorized
for  issuance  under the BOKF 2000 Plan.  I have  reviewed  BOKF's  Registration
Statement on Form S-8, BOKF's  Certificate of Corporation,  BOKF's By-laws,  and
such corporate  proceedings of BOKF as I have deemed appropriate for purposes of
rendering  this  opinion.  In my opinion,  upon issuance of the shares of Common
Stock pursuant to the terms of the BOKF 2000 Plan,  such shares will be duly and
validly issued,  fully paid and non- assessable.  I hereby consent to the filing
of this opinion as an exhibit to the Registration Statement.



                                   Sincerely,

                              /s/ Frederic Dorwart

                                Frederic Dorwart




