St. Mary's Diocesan School for Girls is an Anglican private boarding school for girls situated in Hillcrest, Pretoria in the Gauteng province of South Africa, St Mary's DSG was founded in 1879 by the Rt Revd Henry Bousfield, the first Bishop of Pretoria. For 75 years of its existence the school was run by the nuns of the Community of St Mary the Virgin, The brother school is St. Alban's College.