Mount St. Mary's may refer many institutions. Mount St. Mary's College may be:
- Mount St. Mary's College, a private, independent, post-secondary, Roman Catholic liberal arts college, primarily for women, in Los Angeles
- Mount St Mary's College, a private, independent, secondary, Roman Catholic coeducational boarding school, at Spinkhill, near Sheffield, England
Mount St. Mary's School may be:
- Mount St Mary's School, a private, Roman Catholic boy's school run by Patrician Brothers, at Delhi Cantonment, in India
- Mount St. Mary High School, a private, Roman Catholic high school supported by the Archdiocese of Oklahoma City and the Sisters of Mercy.
Mount St. Mary's University may be:
- Mount St. Mary's University, a Roman Catholic liberal arts university in Emmitsburg, Maryland
Mount St. Mary's Seminary may be:
- Mount St. Mary's Seminary of the West, a Roman Catholic seminary and a division of the Athenaeum of Ohio, in Cincinnati
- Mount St. Mary's Seminary and College, now Mount St. Mary's Seminary of Mount St. Mary's University, in Emmitsburg, Maryland
Mount Saint Mary College may be:
- Mount Saint Mary College, a private, independent, Judeo-Christian college, in Newburgh, New York
