St Mary's, Bryanston Square, is a Church of England church dedicated to the Virgin Mary in Bryanston Square, London. It is also the name of a related Church of England primary school which was originally founded next to it. It was built as one of the Commissioners' churches in 1823-1824 and was designed by Robert Smirke to seal the vista from the lower end of Bryanston Square. It is a brick building, with a stone portico and tower and listed grade I. The church cost £19,955 (£1,530,000 as of 2014), and the Church Building Commission gave a grant of £14,955 towards this.