Okla. Stat. tit. 51 § 36.1
Every officer and employee of the State of Oklahoma, or of a county, school district, municipality, public agency, public authority, or public district thereof, who, on or after July 1, 1953, is appointed or elected to office, or who after said date is employed, for a continuous period of thirty (30) days or more, in order to qualify and enter upon the duties of his office or employment and/or receive compensation, if any, therefor, shall first take and subscribe to the loyalty oath or affirmation required by this act and file the same as hereinafter set forth. Provided, that a public employee who is employed or whose employment is extended on a fiscal year basis and who has duly taken and filed the oath required by this act in order to qualify for and enter upon, or continue in, the duties of his employment, need not again take and file such an oath so long as his said employment, or reemployment is continuous or consecutive.
Okla. Stat. tit. 51, § 36.1