SECOND AMENDMENT
                                       OF
                                RIGHTS AGREEMENT


     This Second Amendment (this "Amendment") of the Rights Agreement (as
defined below) is made and entered into as of the 14 day of August 2002, by and
between Unit Corporation, a Delaware corporation (the "Company"), and Mellon
Investor Services L.L.C., as "Rights Agent" under the Rights Agreement.

                                    RECITALS:

     WHEREAS, on May 19, 1995, the Board of Directors of the Company declared a
dividend of one stock purchase right (a "Right") for each outstanding share of
common stock, $.20 par value of the Company to the stockholders of record at the
close of business on May 31, 1995, with each Right entitling the registered
holder to purchase from the Company one one-hundredth of a share of the Series A
Participating Cumulative Preferred Stock of the Company, or a combination of
securities and assets of equivalent value, upon the terms and subject to the
conditions set forth in a Rights Agreement, dated as of May 19, 1995, between
the Company and Chemical Bank as Rights Agent, as subsequently amended by the
First Amendment of Rights Agreement, dated as of June 7, 2001, between the
Company and Mellon Investor Services L.L.C., successor to Chemical Bank as
Rights Agent (as so amended, the "Rights Agreement"); and

     WHEREAS, the Board of Directors deems it advisable and in the best
interests of the Company and its stockholders to amend certain provisions of the
Rights Agreement; and

     WHEREAS, no Person (as such term is defined in the Rights Agreement) has
become an Acquiring Person; and

     WHEREAS, the Company desires to amend the Rights Agreement as set forth
below;

     NOW, THEREFORE, the undersigned, in consideration of the premises,
covenants and agreements contained herein and in the Rights Agreement, and other
good, sufficient and valuable consideration, the receipt and sufficiency of
which are hereby acknowledged, do hereby agree as follows:

Each of the following sections or provisions of the Rights Agreement is hereby
amended as follows:

(A). The definition of an "Acquiring Person", as defined in Section 1, is
amended to read as follows:

      "Acquiring Person" shall mean any Person who or which, alone or together
      with all Affiliates and Associates of such Person, shall be the Beneficial
      Owner of more than 15% of the Common Shares then outstanding, but shall
      not include the Company, any Subsidiary of the Company, any employee
      benefit plan of the Company or of any of its Subsidiaries, any Person
      holding Common Shares for or pursuant to the terms of any such employee

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      benefit plan or a Permitted Investor; provided, however, that (i) if the
      Board of Directors of the Company determines in good faith that a Person
      who would otherwise be an "Acquiring Person" became the Beneficial Owner
      of a number of Common Shares such that the Person would otherwise qualify
      as an "Acquiring Person" inadvertently (including, without limitation,
      because (A) such Person was unaware that it beneficially owned a
      percentage of Common Shares that would otherwise cause such Person to be
      an "Acquiring Person" or (B) such Person was aware of the extent of its
      Beneficial Ownership of Common Shares but had no actual knowledge of the
      consequences of such Beneficial Ownership under this Agreement) and
      without any intention of changing or influencing control of the Company,
      then such Person shall not be deemed to be or to have become an "Acquiring
      Person" for any purposes of this Agreement unless and until such Person
      shall have failed to divest itself, as soon as practicable (as determined,
      in good faith, by the Board of Directors of the Company), of Beneficial
      Ownership of a sufficient number of Common Shares so that such Person
      would no longer otherwise qualify as an "Acquiring Person"; and (ii) no
      Person shall become an "Acquiring Person" as the result of an acquisition
      of Common Shares by the Company which, by reducing the number of shares
      outstanding, increases the proportionate number of Common Shares
      beneficially owned by such Person to more than 15% of the Common Shares
      then outstanding (or in the case of a Permitted Investor, more than 23% of
      the Common Shares then outstanding), provided, however, that if a Person
      shall become the Beneficial Owner of more than 15% of the Common Shares
      then outstanding (or in the case of a Permitted Investor, more than 23% of
      the Common Shares then outstanding) by reason of such share acquisitions
      by the Company and shall thereafter become the Beneficial Owner of any
      additional Common Shares (other than pursuant to a dividend or
      distribution paid or made by the Company on the outstanding Common Shares
      or pursuant to a split or subdivision of the outstanding Common Shares),
      then such Person shall be deemed to be an "Acquiring Person" unless upon
      becoming the Beneficial Owner of such additional Common Shares such Person
      does not beneficially own more then 15% of the Common Shares then
      outstanding (or in the case of a Permitted Investor, more than 23% of the
      Common Shares then outstanding).

(B). Section 1 is amended by adding a new subsection thereto, which shall read
as follows:

      "Permitted Investors" shall mean the Kaiser Francis Charitable Income
      Trust B and George B. Kaiser for so long as such Persons, together with
      their respective Affiliates and Associates, collectively shall be the
      Beneficial Owners of greater than 15%, but not more than 23%, of the
      Common Shares then outstanding, provided that all such Persons shall cease
      to be Permitted Investors at such time, after the initial issuance of
      Common Shares to any such Person pursuant to the transactions contemplated
      by the (i) Amended and Restated Stock Purchase Agreement dated as of June
      24, 2002 between Unit Corporation and Kaiser Francis Charitable Income
      Trust B, and (ii) Amended and Restated Share Purchase Agreement dated as
      of June 24, 2002 between Unit Corporation and George B. Kaiser, when such
      Persons shall collectively become the Beneficial Owners of less than 15%
      of the Common Shares then outstanding.

     This Amendment shall be binding upon, and shall inure to the benefit of,
the parties hereto and their respective successors and assigns.

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<PAGE>
     This Amendment may be executed in counterparts, each of which shall be
deemed an original, but all of which shall constitute one and the same
instrument.
     Except as hereby amended, the Rights Agreement shall remain in full
force and effect.

     This Amendment shall be governed by, and interpreted in accordance with,
the laws of the State of Delaware, without regard to principles of conflict of
laws.

     IN WITNESS WHEREOF, the parties hereto have caused this Amendment to be
duly executed as of the day and year first above written.

Unit Corporation                         Mellon Investor Services L.L.C.


------------------------------           ----------------------------
By: John G. Nikkel                                              By:
Its: Chief Executive Officer                                    Its:
























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