Exhibit 31.1
   Certification of Chief Executive Officer Pursuant to Section 302 of the
                              Sarbanes Oxley Act


I, Michael R. Sand, certify that:

1.   I have reviewed this Form 10-Q of Timberland Bancorp, Inc.;

2.   Based on my knowledge, this report does not contain any untrue statement
     of 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(s) 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 on 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(s) 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
     functions):

     (a) All significant deficiencies and material weaknesses in the design or
     operation of internal control over financial reporting which are 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: May 10, 2011

                                          /s/ Michael R. Sand
                                          -------------------------------
                                          Michael R. Sand
                                          Chief Executive Officer

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