EXHIBIT 12.1

                                  Certification

         I, Sterling Du, certify that:

         1. I have reviewed this annual report on Form 20-F of O2Micro
International Limited;

         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 company as of,
and for, the periods presented in this report;

         4. The company'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
company 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 company,
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 company'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 company's
internal control over financial reporting that occurred during the period
covered by the annual report that has materially affected, or is reasonably
likely to materially affect, the company's internal control over financial
reporting; and

         5. The company's other certifying officer and I have disclosed, based
on our most recent evaluation of internal control over financial reporting, to
the company's auditors and the audit committee of the company'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 company'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 company's
internal control over financial reporting.

Dated: June 18, 2007                     By: /s/ STERLING DU
                                         ---------------------------------------
                                         Sterling Du
                                         President and Chief Executive Officer