Exhibit 31(a)
                     Rule 13a-14(a)/15d-14(a) Certification


    I, Rick Green, certify that:

1.       I have reviewed this quarterly report on Form 10-Q of Southwest
         Bancorp, Inc.;

2.       Based on my knowledge, this report does not contain any untrue
         statement of a material fact or omit to state a material fact necessary
         to make the statements made, in light of the circumstances under which
         such statements were made, not misleading with respect to the period
         covered by this report;

3.       Based on my knowledge, the financial statements, and other financial
         information included in this report, fairly present in all material
         respects the financial condition, results of operations and cash flows
         of the registrant as of, and for, the periods presented in this report;

4.       The registrant's other certifying officer and I are responsible for
         establishing and maintaining disclosure controls and procedures (as
         defined in Exchange Act Rules 13a-15(e) and 15d-15(e)) and internal
         control over financial reporting (as defined in Exchange Act Rules
         13a-15(f) and 15d-15(f)) for the registrant and have:

         a)  Designed such disclosure controls and procedures, or caused such
             disclosure controls and procedures to be designed under our
             supervision, to ensure that material information relating to the
             registrant, including its consolidated subsidiaries, is made known
             to us by others within those entities, particularly during the
             period in which this report is being prepared;

         b)  Designed such internal control over financial reporting, or caused
             such internal control over financial reporting to be designed under
             our supervision, to provide reasonable assurance regarding the
             reliability of financial reporting and the preparation of financial
             statements for external purposes in accordance with generally
             accepted accounting principles;

         c)  Evaluated the effectiveness of the registrant's disclosure controls
             and procedures and presented in this report our conclusions about
             the effectiveness of the disclosure controls and procedures as of
             the end of the period covered by this report based upon such
             evaluation; and

         d)  Disclosed in this report any change in the registrant's internal
             control over financial reporting that occurred during the
             registrant's most recent fiscal quarter that has materially
             affected, or is reasonably likely to materially affect, the
             registrant's internal control over financial reporting; and

5.       The registrant's other certifying officer and I have disclosed, based
         on our most recent evaluation of internal control over financial
         reporting, to the registrant's auditors and the audit committee of the
         registrant's board of directors (or persons performing the equivalent
         function):

         a)  All significant deficiencies and material weaknesses in the design
             or operation of internal controls over financial reporting which
             are reasonably likely to adversely affect the registrant's ability
             to record, process, summarize and report financial information; and

         b)  Any fraud, whether or not material, that involves management or
             other employees who have a significant role in the registrant's
             internal control over financial reporting.

    Date:  November 7, 2005              /s/ Rick Green
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                                        Rick Green
                                        President and Chief Executive Officer
                                        (Principal Executive Officer)