EXHIBIT 99.0

                                 August 23, 2002

BOK Financial Corporation
Bank of Oklahoma Tower
Boston Avenue at Second Street
Tulsa, Oklahoma 74172

To the Board of Directors:

         I hereby consent to being named as a person about to become an advisory
director of BOK Financial Corporation ("BOK Financial") and later a director of
BOK Financial, in connection with the consummation of the merger (the "Merger")
of Bank of Tanglewood, N.A., a national banking association ("Tanglewood"), with
and into TW Interim National Bank, a wholly owned subsidiary of BOK Financial,
pursuant to the Agreement and Plan of Merger, dated as of May 15, 2002, by and
among BOK Financial, Tanglewood and TW Interim National Bank, in the
Registration Statement on Form S-4 filed by BOK Financial with the Securities
and Exchange Commission in connection with the Merger (the "Registration
Statement"), and to the filing of this consent as an exhibit to the Registration
Statement.

                                                    Sincerely,

                                                    /s/ ROBERT G. GREER
                                                    ----------------------------
                                                    Robert G. Greer