Exhibit 10.4 (f)

                            BOK FINANCIAL CORPORATION
                  Third Amendment to 1991 Employment Agreement

      This amendment to 1991  Employment  Agreement  (the "Third  Amendment") is
made this ____ day of December  2006 (the "Third  Amendment  Date")  between the
following parties (the "Parties"):

            i.    Stanley A. Lybarger, an individual residing in Tulsa, Oklahoma
                  ("Executive"); and,

            ii.   Bank of Oklahoma, National Association ("Bank").

      The Bank and Executive,  in exchange for the promises  hereafter set forth
and other good and valuable consideration (the receipt and adequacy of which the
Parties hereby acknowledge),  and intending to be legally bound hereby, agree as
follows:

(1)   Purpose of this Agreement. The Parties have heretofore entered in (i) that
      certain Employment Agreement effected June 7, 1991 and signed December 17,
      1991  (the  "Employment  Agreement"),   (ii)  that  certain  Amendment  to
      Employment  Agreement  dated July 31,  2001 (the "First  Amendment"),  and
      (iii) that certain Second  Amendment to 1991  Employment  Agreement  dated
      March  31,  2003 (the  "Second  Amendment").  The  purpose  of this  Third
      Amendment is to (i) amend the Employment  Agreement as herein provided and
      (ii) to supersede in their  entirety  the First  Amendment  and the Second
      Amendment.  BOK Financial  Corporation ("BOKF") owns all of the issued and
      outstanding capital stock of Bank.

(2)   First Amendment and Second  Amendment.  The First Amendment and the Second
      Amendment are hereby superseded in their entirety by this Third Amendment.
      For sake of clarity, BOK acknowledges that:

            (i)   Executive has recruited  one or more  candidates  who have the
                  qualifications  to serve as chief  operating  officer for BOKF
                  (collectively the "COO");

            (ii)  The COO currently  possesses the experience and qualifications
                  on the basis of which the Chairman of the Board and  Executive
                  mutually  agree it is  reasonable  to  assume  the COO  should
                  become qualified to be the Chief Executive  Officer of BOKF at
                  Termination.

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(3)   Special  Provisions   Respecting   Executive's   Employee  Stock  Options.
      Executive has heretofore been awarded options to acquire BOKF Common Stock
      pursuant to the BOKF 1997 Stock  Option  Plan,  the BOKF 1996 Stock Option
      Plan, the BOKF 1995 Stock Option Plan, the BOKF 1994 Stock Option Plan and
      the BOKF 1993 Stock Option Plan and may be awarded options to acquire BOKF
      Common Stock pursuant to future BOKF stock option plans (collectively, the
      "Stock Option Plans" and the "Stock Options"). In addition,  Executive may
      hereafter be issued restricted or performance  shares of BOKF Common Stock
      ("Restricted   Shares")  pursuant  to  one  or  more  BOKF  restricted  or
      performance share plans ("Performance  Share Plans").  Notwithstanding any
      provisions  of the Stock  Option Plans or  Performance  Share Plans to the
      contrary,  all Stock  Options and all  Restricted  Shares  which have been
      issued  to  the  Executive  shall,  subject  to the  following  conditions
      precedent vest, on the Termination Date:

      (a)   Unless  terminated  by BOKF without cause or terminated by Executive
            pursuant to Paragraph 6(a) of the Employment Agreement ("Termination
            By the Executive  Following  Occurrence  of a  Termination  Event"),
            Executive shall have  satisfactorily (as determined by the agreement
            of  the  Chairman  of the  Board  and  Executive)  served  as  Chief
            Executive Officer until December 15, 2011(herein called "Termination
            Date");

      (b)   The Chairman of the Board and Executive, each in the exercise of his
            good faith judgment, continue to agree as of July 1 of year from and
            after the Amendment Date (each an "Anniversary  Date"), that the COO
            is qualified to be the Chief Executive Officer of the Corporation at
            Termination;

      (c)   The Chairman of the Board and Executive, each in the exercise of his
            good faith  judgment,  agree that BOKF has  maintained  satisfactory
            performance  through the Termination  Date, giving due consideration
            to the  performance of the United States economy in general and peer
            group financial institutions in the United States in particular;

      (d)   In the event the Chairman of the Board and Executive do not, each in
            the  exercise  of his good  faith  judgment,  reach  the  agreements
            described in  sub-paragraphs  (a),  (b) and (c) above,  the issue or
            issues shall be presented to the full Board of Directors of Bank for
            determination  and the  determination of the Bank Board of Directors
            shall be binding upon Bank and Executive;

      (e)   Unless the Chairman of the Board shall  advise  Executive in writing
            on or before  each  applicable  Anniversary  Date  that a  condition
            precedent  described in sub-paragraphs  (a), (b), and/or (c) has not
            been met, such condition precedent shall be deemed to have been met.

      (f)   Notwithstanding  any  provisions  of the Stock  Option  Plans to the
            contrary, all Stock Options which have been awarded to Executive and
            which have

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            vested  as  of  the  Termination  Date  (whether   pursuant  to  the
            provisions  of  the  preceding   subparagraph  or  otherwise)  shall
            terminate,  if not sooner  exercised,  fifteen (15) months following
            Termination Date.

(4)   Amendment of Paragraph 6(b) of Employment Agreement. Paragraph 6(b) of the
      Employment  Agreement  is hereby  amended by  inserting  in the third line
      thereof  following the words "may terminate this  Agreement" and preceding
      the words "as follows" the words "only after December 15, 2011".

(5)   Amendment of Paragraph 3(b) of Employment Agreement. Paragraph 3(b) of the
      Employment  Agreement is amended by substituting the word "executives" for
      the word "employees" in the sixth line thereof.

(6)   Amendment of Paragraph 2(b) of Employment Agreement. Paragraph 2(b) of the
      Employment  Agreement is hereby amended by inserting the word "materially"
      immediately preceding the word "interferes" in the fourth line thereof.

(7)   Amendment of  Paragraph  5(b)(i)(C)  of  Employment  Agreement.  Paragraph
      5(b)(i)(C) of the Employment  Agreement is hereby amended by adding at the
      end thereof  following the words  "fraudulent  act" the words  "materially
      injurious to Bank."

(8)   Amendment  of  Paragraph  5(b)(ii)  of  Employment  Agreement.   Paragraph
      5(b)(ii) is hereby deleted in its entirety and there is hereby substituted
      therefore the following:

            For purposes of this paragraph 5(b):

            (A)   any act or omission to act by  Executive  in reliance  upon an
                  opinion  of  counsel  to the Bank or upon a  directive  of the
                  Board of  Directors of the Bank or of BOKF shall not be deemed
                  to be willful; and,

            (B)   no failure to act  described  in paragraph  5(b)(i)(A)  or act
                  described  in  paragraph  5(b)(i)(B)  shall be deemed  willful
                  unless  written notice thereof has been given to Executive and
                  Executive has been given a reasonable period of time to cure.

(9)   Executive's  Continued  Involved with BOKF Beyond Termination and Prior to
      Age 65. In the event of  Termination  prior to reaching age 65,  Executive
      will be  permitted  to continue to be involved in the business and affairs
      of BOKF as a part-time special employee, consultant, director with special
      duties,  or in some other  capacity to the extent  reasonably  required to
      permit Executive to continue to participate in BOKF's employee health care
      benefits until age 65, but only for so long as Executive  continues to owe
      a duty of  loyalty  to  BOKF.  The  costs of such  participation  shall be
      allocated between Bank and Executive equitably depending upon the level of
      Executive's  continued  involvement  with  BOKF.  In the  event  Executive
      continues to be involved in any such capacity, all

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      compensation  due  Executive  which is  deferred  compensation  within the
      meaning  of Section  409A of the  Internal  Revenue  Code shall be paid to
      Executive  on a date which is the later of (i) the date  provided  in that
      certain 409A Deferred Compensation  Agreement dated March 15, 2005 between
      Executive  and  BOK  Financial  Corporation  and  (ii) a date  as  soon as
      administratively  possible within the 45 day period after the later of six
      months following the date such involvement shall cease.

(10)  Agreement Not To Compete.  In consideration  for the foregoing,  Executive
      agrees not to Compete  (as  hereafter  defined)  for a period of two years
      following  Termination  except  in the  case of  Termination  by the  Bank
      without cause.  Executive  agrees that (i) the  restrictions  imposed upon
      Executive by this Non-Competition Agreement are essential and necessary to
      ensure BOKF continues to enjoy the goodwill of the Bank, and (iii) all the
      restrictions   (including   particularly   the   time   and   geographical
      limitations) are fair and reasonable.

      (a)   As used herein,  Compete  means to directly or  indirectly  (whether
            individually  or  as  an  officer,  director,   employee,   partner,
            stockholder,  creditor, agent, or representative of other persons or
            entities) (i) engage in the banking  business  generally,  or in any
            business in which the Bank or any of the Bank's affiliates has as of
            the date of such termination  engaged,  in any metropolitan  area or
            any County contiguous thereto in which the Bank or any of the Bank's
            affiliates  maintains an office as of the date of such  termination,
            (ii)  solicit  clients  of Bank or  Bank's  affiliates  for  banking
            business  generally  or for any business in which the Bank or any of
            Bank's  affiliates have engaged as of the date of such  termination,
            or (iii) solicit any employee of Bank or any of Bank's affiliates to
            seek  employment  with any person or entity  except the Bank and its
            affiliates,  whether,  in either  case,  such  solicitation  is made
            within or without the area described herein.

      (b)   Executive  agrees  that any  remedy  at law for any  breach  of this
            promise  would be  inadequate  and, in the event of any such breach,
            BOKF shall be entitled to both  immediate and  permanent  injunctive
            relief  without  the  necessity  of  posting  any bond  therefor  to
            preclude  any such breach (in  addition to any remedies of law which
            BOKF may be entitled).

      (c)   Executive agrees that the provisions of this paragraph were accepted
            and  agreed  to in the First  Amendment  as of July 31,  2001,  that
            Executive  has  accepted  and  enjoyed  the  benefit  of  the  First
            Amendment  since  July 31,  2001,  and that the  restatement  of the
            obligations  of this  Paragraph  in this Third  Amendment  shall not
            adversely  affect  the  ability  of  BOK  or  BOKF  to  enforce  the
            provisions hereof.

(11)  Ratification of Employment Agreement.  As amended by this Third Amendment,
      the  Employment  Agreement  shall  remain  in full  force  and  effect  in
      accordance with its terms.

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(12)  Miscellaneous  Provisions The  Miscellaneous  Provisions of Paragraph 8 of
      the Employment  Agreement shall apply to this Third  Amendment;  provided,
      however, this Agreement is made for the benefit of BOKF and BOK.

Dated as of the Agreement Date.

                                        Bank of Oklahoma, National Association

                                        By
                                           -----------------------------------

                                        Stanley A. Lybarger


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