St Paul's School is a selective independent day school (with limited boarding) for boys aged 13–18, founded in 1509 by John Colet and located on a 43-acre site by the Thames in London.
St Paul's was one of nine English schools investigated by the Clarendon Commission, which subsequently became known as the Clarendon schools. However, the school successfully argued that it was a private school and consequently was omitted from the Public Schools Act 1868, as was Merchant Taylors', the other day school within the scope of Lord Clarendon's terms of reference. Since 1881, St Paul's has had its own preparatory school, St Paul's Juniors (formerly Colet Court), which since 1968 has been located on the same site.