St Mary's College, Southampton is an independent day school for boys and girls in Southampton, Hampshire, England. The school was founded in 1922 as a Roman Catholic independent school for boys. In 1992 the junior department started taking girls and in 2000 the senior department was opened to girls, approximately 25% of the pupils are now girls and the school also includes Charlton House Preparatory School and Charlton Nursery. The schools mission is to 'seek to foster the growth of the whole person within a Mennaisian community'. Former pupils are known as Old Simmarians.