Okla. Stat. tit. 22 § 718
A witness who appears from another state to testify in this state in a criminal case or proceeding pursuant to a subpoena issued in accordance with the provisions of the Uniform Act to Secure the Attendance of Witnesses from Without a State in Criminal Proceedings, Section 721 et seq. of this title, shall be reimbursed as prescribed by law for travel and expenses at rates not to exceed those prescribed by law for reimbursement of state employees traveling interstate. Such witnesses shall receive the same fees as witnesses who appear from this state, pursuant to Section 81 of Title 28 of the Oklahoma Statutes. If the witness is under eighteen (18) years of age, or requires the assistance of a guardian due to age or infirmity, the travel expenses of one parent or guardian may be reimbursed also. The parent or guardian shall not be entitled to a witness fee. Upon conviction, such fees and mileage shall be taxed as costs, collected and deposited as other costs in the case.
Okla. Stat. tit. 22, § 718