Okla. Stat. tit. 26, § 26-12-111: Vacancies in county elective offices

A. Whenever a vacancy shall occur in the office of a county

commissioner, the vacancy shall be filled at a special election to

be called by the Governor within thirty (30) days after the vacancy

occurs. Provided, no special election shall be called if the

vacancy occurs in an even-numbered year if the term of the office

expires the following year. In such case, the candidate elected to

the office at the Primary Election, runoff Primary Election, or the

regular General Election shall be appointed by the Governor as soon

as practical after the applicable election to fill the unexpired

term.

B. Whenever a vacancy shall occur in any elective county office

of any county in this state having a population of more than the

population figure specified in subsection B of Section 10 of Title

51 of the Oklahoma Statutes, the vacancy shall be filled at a

special election to be called by the Governor within thirty (30)

days after the vacancy occurs. Provided, no special election shall

be called if the vacancy occurs in an even-numbered year if the term

of the office expires the following year. In such case, the

candidate elected to the office at the Primary Election, runoff

Primary Election, or the regular General Election shall be appointed

by the Governor as soon as practical after the applicable election

to fill the unexpired term.