Okla. Stat. tit. 19 § 510
Any person, otherwise qualified, who has been a resident of the State of Oklahoma for two (2) years, has been a registered voter of the party whose nomination he or she seeks, or a registered Independent, within the county from which such person seeks election for the six (6) months next preceding the first day of the filing period, is at least twenty-five (25) years of age next preceding the date of filing for office, possesses at least a high school education and has served as a duly certified peace officer, in a full-time capacity, for a period of four (4) years or more prior to the date of filing for the office of county sheriff, shall be eligible to hold the office of county sheriff or to file therefor. Within twelve (12) months of taking office, all newly elected or appointed sheriffs shall complete a sheriff's administrative school which has been developed by the Oklahoma Sheriffs' Association and which has been approved by the Council on Law Enforcement Education and Training (CLEET). Failure to complete the sheriff's administrative school within the specified period shall preclude the new sheriff from obtaining CLEET certification. New sheriffs with prior CLEET certification, who fail to attend the sheriff's administrative school, shall have their CLEET certification revoked. Provided, however, the provisions of this section relating to qualifications shall not apply to any person serving as a county sheriff or to any person previously serving as county sheriff prior to the adoption of this statute.
For purposes of this section, "peace officer" shall mean a full-time duly appointed or elected officer who is paid for working more than twenty-five (25) hours per week and whose duties are to preserve the public peace, protect life and property, prevent crime, serve warrants, and enforce state, federal or military laws and local ordinances of this state or any political subdivision thereof.
Okla. Stat. tit. 19, § 510