The O'Brien Institute is a building complex in Dublin, Ireland. It was built 1880–1883. The purpose of the building was to serve as an orphan home and school, financed by a trust that was founded by Bridget O'Brien in 1876.The last of the boarders (four in all) left in 1976,when the school was closed for good,at the time it was run by the Christian Brothers. The architect was John Joseph O'Callaghan (+ 1905).