<PAGE>

                                                                    Exhibit 10.2


                     SOUTHWEST BANCORP, INC AND AFFILIATES
                AMENDED AND RESTATED SEVERANCE COMPENSATION PLAN

         The Stillwater National Bank and Trust Company Severance Compensation
Plan originally was made and entered into by Stillwater National Bank and Trust
Company, for the benefit of certain officers, key management and highly
compensated employees effective June 24, 1993, and was amended and restated
effective July 24, 1997. It is hereby further amended and restated as of August
26, 2004. The purpose of the Plan as amended and restated is to protect and
retain certain officers, key management and highly compensated employees of
Southwest Bancorp, Inc. ("Southwest") and its affiliates in the event of a
Change in Control and to reward those employees for loyal service to Southwest
by providing for severance compensation to them upon their termination of
employment after a Change in Control as provided herein.

                                   ARTICLE I
                                  DEFINITIONS

         The terms defined in this Article shall have the meanings given below:

         1.1      AFFILIATE means any corporation, partnership, business trust,
                  or other business entity of which Southwest has or acquires
                  direct or indirect voting power over 50 percent or more of the
                  outstanding common shares or equivalent voting interests, and
                  shall include, without limitation, SNB-Stillwater and
                  SNB-Wichita.

         1.2      ANNUAL EARNINGS means one-year's Earnings at the higher of the
                  rate in effect;

                  (a)      upon the Change in Control; or

                  (b)      immediately prior to the Participant's Qualified
                           Termination of Service.

         1.3      BOARD means:

                  (a)      the Board of Directors of Southwest; and

                  (b)      the Board of Directors of the Southwest Company that
                           employs, or intends to employ, the Participant at the
                           date the Participant is selected for participation in
                           the Plan, unless that Southwest Company does not
                           execute the Plan.

         1.4      CHANGE IN CONTROL means:

                  (a)      the date any entity or person, including a group as
                           defined in Section l3(d)(iii) of the Securities
                           Exchange Act of 1934 shall become the beneficial
                           owner of, or shall have obtained voting control over,
                           50 percent or more of the outstanding common shares
                           of either Southwest or SNB-Stillwater;

                  (b)      the date the shareholders of either Southwest or
                           SNB-Stillwater approve a definitive agreement (i) to
                           merge or consolidate either Southwest or
                           SNB-Stillwater with or into another corporation in
                           which either Southwest or SNB-Stillwater,
                           respectively, is not the continuing or surviving
                           corporation or pursuant to which any common shares of
                           either Southwest or SNB-Stillwater would be converted
                           into cash, securities, or other property of another
                           other than a merger of either Southwest or
                           SNB-Stillwater in which holders of common shares
                           immediately prior to the merger have the same
                           proportionate interest of common stock of the
                           surviving corporation immediately after the merger as
                           immediately before, or (ii) to sell or otherwise
                           dispose of substantially all of the assets of either
                           Southwest or SNB-Stillwater; or


                                       1
<PAGE>

                  (c)      the date there shall have been change in a majority
                           of the Board of either Southwest or SNB-Stillwater
                           within a 12 month period unless the nomination of
                           each new director was approved by the vote of
                           two-thirds (2/3) of directors then still in office
                           who were in office at the beginning of the 12 month
                           period.

         1.5      CODE means the Internal Revenue Code of 1986, as amended.

         1.6      COMMITTEE means the Committee appointed by the respective
                  Board to administer this Plan. Any function exercisable by
                  such Committee may also be exercised by the Board.

         1.7      EARNINGS means only the annual rate of salary (base cash
                  compensation) payable to the Participant by Southwest and any
                  Affiliates of the Bank, and shall not include overtime, bonus,
                  commissions, or any non-cash amounts (including amounts
                  attributable to stock options). Earnings shall not be reduced
                  by amounts excluded from gross income under Sections 125,
                  402(a)(8) or 402(h) or limited as provided under Section
                  401(a)(17) of the Internal Revenue Code of 1986, as amended
                  ("Code").

         1.8      EFFECTIVE DATE means June 24, 1993.

         1.9      GOOD REASON shall mean:

                  (a)      a reduction in Participant's Earnings in effect
                           immediately prior to a Change in Control or as
                           increased thereafter;

                  (b)      the assignment of Participant without Participant's
                           consent to (i) a location outside of the metropolitan
                           statistical area ("MSA") in which such Participant
                           was assigned at the date of the Change in Control, or
                           (ii) if Participant was not assigned in an MSA at
                           such date, a location more than 75 miles from the
                           location to which Participant was assigned at the
                           date of the Change in Control;

                  (c)      a material reduction in the authority or
                           responsibility that Participant had immediately prior
                           to the Change in Control; or

                  (d)      a material reduction in the level of incentive
                           compensation or benefits of a Participant from those
                           in effect immediately prior to a Change in Control
                           except such reductions as are applicable to all
                           employees or key executives generally and which do
                           not have a disproportionate effect on Participant.

         1.10     PARTICIPANT means an employee of a Southwest Company selected
                  for participation in the Plan by the Board or Committee.

         1.11     PLAN means this Amended and Restated Severance Compensation
                  Plan and amendments hereto.

         1.12     PRINCIPAL EMPLOYER means the Southwest Company that provided
                  the majority of earnings to a Participant during the twelve
                  months prior to a Qualifying Termination of Service,
                  Termination for Cause, or request for arbitration, as the case
                  may be, and any successor thereto that is a Southwest Company.

         1.13     QUALIFYING TERMINATION OF SERVICE means either:

                  (a)      a Participant's involuntary termination of employment
                           with the Bank and its subsidiaries or their
                           successors; or

                  (b)      a Participant's voluntary termination of employment
                           with the Bank and its subsidiaries for Good Reason,


                                       2
<PAGE>

                  in either case within two (2) years following the first Change
                  in Control occurring after the Effective Date. Qualifying
                  Termination of Service does not include any change in the
                  Participant's employment status due to disability or death or
                  a Termination for Cause.

         1.14     SNB-STILLWATER means Stillwater National Bank and Trust
                  Company and any successor corporation.

         1.15     SNB-WICHITA means SNB Bank of Wichita and any successor
                  corporation.

         1.16     SOUTHWEST means Southwest Bancorp, Inc., and any successor
                  corporation.

         1.17     SOUTHWEST COMPANY means Southwest Bancorp, Inc. or any of its
                  Affiliates.

         1.18     TERMINATION FOR CAUSE means a Participant's termination of
                  employment with any Southwest Company because of:

                  (a)      the continued failure by the Participant to devote
                           reasonable time and effort to the performance of
                           Participant's duties (other than a failure resulting
                           from the Participant's incapacity due to physical or
                           mental illness) after written demand for improved
                           performance has been delivered to the employee by the
                           Participant's Principal Employer which specifically
                           identifies:

                           (i)      how the Participant has not devoted
                                    reasonable time and effort to the
                                    performance of Participant's duties; or

                           (ii)     the willful engaging by Participant in
                                    misconduct that is materially injurious to
                                    any Southwest Company, monetarily or
                                    otherwise; or

                           (iii)    the Participant's ineligibility for coverage
                                    under a banker's blanket bond policy
                                    maintained on or on behalf of any Southwest
                                    Company that is a depository institution.

                  Unless such acts caused the Participant to be ineligible for
                  coverage under a banker's blanket bond policy, a Termination
                  for Cause shall not include a termination attributable to: (i)
                  bad judgment or negligence on the part of the Participant
                  other than habitual negligence; or (ii) an act or omission
                  believed by the Participant in good faith to have been in or
                  not opposed to the best interests of the Southwest Companies
                  and reasonably believed by the Participant to be lawful; or
                  (iii) the good faith conduct of a Participant in connection
                  with a Change in Control (including Participant's opposition
                  to or support of the Change in Control).

                                   ARTICLE II
                                    BENEFITS

         2.1      DESIGNATION OR PARTICIPANTS. The Participants shall be those
                  employees of Southwest or its Affiliates listed on Exhibit A
                  and others designated by the Board or the Committee from time
                  to time as Participants in the Plan.

         2.2      SEVERANCE COMPENSATION.

                  (a)      Upon the Qualifying Termination of Service of any
                           Participant, the terminated Participant shall be
                           entitled to severance compensation equal to the
                           percentage of the Participant's Annual Earnings
                           designated on Exhibit A or by the Board or the
                           Committee at the time the employee is selected for
                           participation in the Plan, but in no event greater
                           than 150% of a Participant's Annual Earnings or the
                           amount which would be deductible by the Southwest
                           Companies under Code Section 280(G), after taking
                           into consideration all payments to such Participant
                           covered by such section. The Severance Compensation
                           shall be paid to the Participant by its Principal
                           Employer in a single, lump sum payment promptly after
                           Participant's Qualifying Termination of Service. All
                           payments of severance benefits shall be reduced by
                           the amount of applicable Federal, State, and local
                           withholding taxes, and FICA and FUTA taxes.


                                       3
<PAGE>

                  (b)      If the Principal Employer of a Participant designated
                           by the Board or the Committee has not executed this
                           Plan, any obligation to that Participant under this
                           Plan not paid by Affiliates of Southwest shall be
                           paid by Southwest.

         2.3      NO FUNDING OR PAYMENTS. All compensation due a Participant
                  under this Plan is unfunded and unsecured and is payable out
                  of general funds of the respective Southwest Company or
                  Companies.

         2.4      TIMING OF PAYMENTS. If severance compensation is not paid
                  within thirty (30) days of the Qualifying Termination of
                  Service, there shall be paid, in addition to such amount,
                  interest on the amount due at a rate of 5% in excess of the
                  prime rate as published in the Wall Street Journal-Southwest
                  Edition from time to time (or at the highest of such rates if
                  a range is published) from the date which is thirty (30) days
                  following the Qualifying Termination of Service to the date of
                  payment.

                                   ARTICLE III
                            MISCELLANEOUS PROVISIONS

         3.1      PLAN ADMINISTRATION. The general administration of this Plan
                  shall be the responsibility of the Committee. The good faith
                  determination of the Committee with respect to the
                  administration of this Plan shall be final and conclusive.

         3.2      NO GUARANTEE OF EMPLOYMENT. Nothing contained herein shall be
                  construed as a contract of employment or be deemed to give any
                  Participant the right to be retained in the employ of any
                  Southwest Company, or to interfere with the rights of any such
                  employer to discharge any individual at any time, with or
                  without cause. No severance compensation shall be payable
                  hereunder as a result of any termination of employment
                  occurring prior to a Change in Control.

         3.3      AMENDMENT AND TERMINATION. The Board may at any time, or from
                  time to time, amend this Plan in any respect or terminate this
                  Plan without restriction and without consent of any
                  Participant or beneficiary, provided, that any such amendment
                  or termination shall not impair the rights of any Participant
                  hereunder without the consent of such Participant. Once a
                  Participant has been selected by the Board, this Plan shall
                  constitute a contract between the Participant and the
                  Southwest Company or Companies that employed participant at
                  the later of the date of such selection or the Participant's
                  first day of employment thereafter by a Southwest Company.

         3.4      NON-ALIENATION OF BENEFITS. No benefit payable hereunder may
                  be assigned, pledged, mortgaged or hypothecated and, except to
                  the extent required by applicable law, no such benefit shall
                  be subject to legal process or attachment for the payment of
                  any claims of a creditor of a Participant.

         3.5      PAYMENT TO REPRESENTATIVES. If any Participant dies after a
                  Qualifying Termination of Service and before receipt of
                  payment hereunder, the severance compensation otherwise due to
                  such Participant shall be payable to Participant's estate. If
                  any individual entitled to receive any benefits hereunder is
                  determined by the Committee or is adjudged to be legally
                  incapable of giving valid receipt and discharge for such
                  benefits, they shall be paid to the duly appointed and acting
                  guardian, if any, and if no such guardian is appointed and
                  acting, to such persons as the Committee may designate. Such
                  payment shall, to the extent made, be deemed a complete
                  discharge for such payments under this Plan.

         3.6      GOVERNING LAW. The provisions of this Plan shall be construed
                  under the laws of the State of Oklahoma except as preempted by
                  federal law.


                                       4
<PAGE>

         3.7      TITLES AND HEADINGS. The titles to articles and headings of
                  sections of this Plan are for convenience of reference and, in
                  case of any conflict, the text of the Plan, rather than such
                  titles and headings, shall control.

         3.8      LEGALITY. No Southwest Company shall have any obligation to
                  make any payments under this plan to the extent such payments
                  would be in violation of Section 18(k)(j) of the Federal
                  Deposit Insurance Act or any other law or regulation directly
                  applicable to the Southwest Company.

         3.9      RESOLUTION OR DISPUTES. Any dispute between a Participant or a
                  Southwest Company or any successor, shall be first submitted
                  to mediation under the Commercial Mediation Rules of the
                  American Arbitration Association, which may be initiated by a
                  written request by Participant or the Participant's Principal
                  Employer. If such dispute is not resolved within sixty days of
                  the written request for mediation, it shall be submitted to
                  arbitration in accordance with the Commercial Arbitration
                  Rules of the American Arbitration Association and judgment
                  upon the award rendered by the arbitrator may be entered in
                  any court having jurisdiction thereof. In connection with such
                  mediation and arbitration, the following rules shall apply:

                  (a)      Any mediation shall be held in the city in which the
                           Participant resides at the time of Submission to
                           mediation;

                  (b)      Any mediation or arbitration shall be conducted by a
                           single person who shall serve as both mediator and
                           arbitrator; and

                  (c)      The costs of any mediation and arbitration shall be
                           borne by the Principal Employer or, if the Principal
                           Employer of a Participant designated by the Board or
                           the Committee has not executed this Plan, any
                           obligation to that Participant under this Plan for
                           such costs not paid by Affiliates of Southwest shall
                           be paid by Southwest.

         IN WITNESS WHEREOF, the undersigned have executed this Agreement this
26th day of August, 2004.

Attest: [seal]                             SOUTHWEST BANCORP, INC.


By:  /s/ Kerby E. Crowell                  By:  /s/Rick Green
     --------------------------------           --------------------------------
     Secretary                                  President and Chief Executive
                                                Officer


                                           STILLWATER NATIONAL BANK AND
Attest: [seal]                             AND TRUST COMPANY


By:  /s/Kerby E. Crowell                   By:  /s/ Rick Green
     --------------------------------           --------------------------------
     Secretary                                  President and Chief Executive
                                                Officer


                                       5
<PAGE>

                                   EXHIBIT A

                                               Severance Compensation Expressed
Participants                                  as a Percentage of Annual Earnings
------------                                  ----------------------------------

Kerby E. Crowell                                             200%

Rick J. Green                                                300%

Steven N. Hadley                                             100%

Rex Horning                                                  100%

Jerry Lanier                                                 200%

Leonard M. McLaughlin                                        100%

Steve M. Peterson                                            100%

Joseph P. Root                                               100%

Kimberly G. Sinclair                                         100%

Gary Teel                                                    100%

Charles Westerheide                                          100%

David L. York                                                100%

Scott B. Jones                                                50%

Sharon L. Knight                                              50%

Elaine E. Skillman                                            50%

Kay W. Smith                                                  50%

                                                            * * *
Pursuant to Resolution of the Board of Directors

Date:  February 24, 2005
       --------------------------


Attest: [seal]                             SOUTHWEST BANCORP, INC.

By:    /s/ Kerby E. Crowell                By:    /s/ Rick Green
       --------------------------------           ------------------------------
       Secretary                                  President and Chief Executive
                                                  Officer


                                           STILLWATER NATIONAL BANK AND
Attest: [seal]                             AND TRUST COMPANY


By:    /s/ Kerby E. Crowell                By:    /s/ Rick Green
       --------------------------------           ------------------------------
       Secretary                                  President and Chief Executive
                                                  Officer


                                       6