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 consists of four houses, each with a different colour, which compete in inter-house events such as hockey, tennis, swimming, athletics, squash, music, debating and theatre.
Junior school houses
Hares (yellow)
Zebras (red)
Springboks (green)
Lions (blue)
Pupils in grade 0 are placed in houses in the first term and stay through grade 7.
High school houses
Clayton (yellow)
Furse (red)
Karney (green)
Phelps (blue)
The house system was introduced in 1934 and students wear their house badges on their blazers with pride. The houses are named after bishops of Johannesburg; Geoffrey Clayton 1934-1949 and Arthur Karney 1922–1933; bishop of Pretoria, Michael Furse 1909–1920 and archbishop of Cape Town, Francis Phelps 1931–1938.
