Okla. Stat. tit. 70 § 5-131
The board of education of every school district in this state is hereby authorized to provide educational courses for all persons and said board is authorized to provide necessary buildings, equipment, and other facilities for such persons. Such educational courses may include grades one to twelve, inclusive, for persons between the ages of six (6) and twenty-one (21) years and may also include nursery and kindergarten classes, junior college grades, vocational and technical instruction, adult and part-time classes and other special classes. The curricula and qualifications of teachers shall be determined by the State Board of Education except as otherwise provided herein. Provided, any district offering educational courses shall charge tuition fees for such courses unless the school district has funds available to pay the cost thereof which are not needed to maintain the common school program.
Okla. Stat. tit. 70, § 5-131