St Mary's School is a South African Anglican private boarding school for girls located in Waverley, Johannesburg. Established in 1888, it is the oldest school in Johannesburg. It was founded by the Anglican clergyman the Rev. John T. Darragh, who also founded its brother school St. John's College, Johannesburg in Houghton ten years later in 1898. St Mary's School writes the Independent Examinations Board exams.