Exhibit 31.1

Certification of Chief Executive Officer (Section 302 Certification)

I,
James C. Holly, certify that:

1. I have reviewed the 2010 Annual Report on Form 10-K (Annual Report) of Sierra
Bancorp (the Registrant);

2. Based on my knowledge, the Annual 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 the Annual Report;

3. Based on my knowledge, the financial statements, and other financial information included in the Annual 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 the Annual 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 the Annual 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 the Annual Report our
conclusions about the effectiveness of the disclosure controls and procedures, as of the end of the period covered by the Annual Report based on such evaluation; and

(d) Disclosed in the Annual 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 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:

(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: March 11, 2011



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|/s/ James C. Holly                                
|James C. Holly
President & Chief Executive Officer