Exhibit 32(a)
                      18 U.S.C. Section 1350 Certification


I hereby certify pursuant to 18 U.S.C. ss. 1350, as adopted pursuant to ss. 906
of the Sarbanes-Oxley Act of 2003, to the best of my knowledge and belief, that
the accompanying Form 10-Q of Southwest Bancorp, Inc. ("Southwest") for the
quarterly period and nine month periods ended September 30, 2005, fully complies
with the requirements of section 13(a) or 15(d) of the Securities Exchange Act
of 1934 (15 U.S.C. 78m or 78o(d)); and that the information contained in this
Form 10-Q fairly presents, in all material respects, the financial condition and
results of operations of Southwest.


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