Exhibit 31.1

                            Certification Required
     by Rules 13a-15 and 15d-15 under the Securities Exchange Act of 1934

I, Michael R. Sand, certify that:

1.  I have reviewed this Annual Report on Form 10-K of Timberland 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(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 (the registrant's fourth
         fiscal quarter in the case of an annual report) 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
         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: December 10, 2010           /s/ Michael R. Sand
                                  -----------------------
                                  Michael R. Sand
                                  Chief Executive Officer

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