Saint Mary's College C.S.Sp. (Congregatio Sancti Spiritus) is an all-boys' primary & secondary school run by the Congregation of the Holy Spirit and located in Rathmines, County Dublin, Ireland. The school was founded in 1890, closed in 1916, and then reopened in 1926. The school colours are blue and white. The Senior School Principal is Denis Murphy and the Senior School Deputy Principal is Brian Moore.