Mount St. Mary High School is co-sponsored by the Religious Sisters of Mercy of the St. Louis Region and the Catholic Archdiocese of Oklahoma City. The co-sponsors govern the school along with a Board of Trustees comprised of parents, alumni, business leaders, community volunteers, and Sisters of Mercy.

Mount St. Mary High School is organized according to the laws of the State of Oklahoma and the United States as a private, Catholic secondary educational institution and is recognized as a private non-profit organization under section 501(c)(3) of the Internal Revenue Code capable of receiving tax-deductible gifts from individuals, corporations, and foundations.

Mount St. Mary High School is accredited by the Oklahoma State Department of Education, as well as the Catholic Archdiocese of Oklahoma City. Mount St. Mary is also a member of the following:

• North Central Association of Colleges and Schools
• National Catholic Education Association
• Mercy Secondary Education Association
• College Board
• National Association of Secondary School Principals
• National Student Assistance Association
• Oklahoma Secondary School Activities Association
• Oklahoma Coaches Association