Okla. Const. art. VII, § 2

The Supreme Court shall consist of nine Justices until the number shall be changed by statute and each Justice shall be from a separate district of the State. Each district shall remain as presently constituted until otherwise provided by Statute. The terms of office of the Justices of the Supreme Court shall be six years and shall commence on the second Monday of January following their election. Those appointed or elected to fill vacancies shall assume office immediately upon qualifying for the office. Each Justice, at the time of his election or appointment, shall have attained the age of thirty years, shall have been a qualified elector in the district for at least one year immediately prior to the date of filing or appointment, and shall have been a licensed practicing attorney or judge of a court of record, or both, in Oklahoma for five years preceding his election or appointment and shall continue to be a duly licensed attorney while in office to be eligible to hold the office. The Justices shall choose from among their members a Chief Justice and a Vice Chief Justice.