Riddlesdown Collegiate (formerly Riddlesdown High School) is a secondary school with academy status located in the Riddlesdown area of the London Borough of Croydon, UK. Riddlesdown is a coeducational school, of 1902 students (311 of those being post–16 students). The school takes its pupils mainly from the Sanderstead, Selsdon, Purley, Kenley, New Addington and South Croydon areas, and specialises in science. Riddlesdown is the largest school in Croydon in terms of pupil numbers.