Sir Thomas Drew (18 September 1838 – 13 March 1910) was an Irish architect.
Thomas Drew was born in Victoria Place, Belfast. He was trained under Sir Charles Lanyon before moving to work in Dublin, where he became principal assistant to William George Murray. In 1865 he became diocesan architect of the united dioceses of Down, Connor and Dromore in 1865, and from then on Church architecture was Drew's principal activity. He was consulting architect for both St. Patrick's Cathedral and Christ Church Cathedral in Dublin.
Among other projects, he was responsible for the design of the Ulster Bank on Dame Street, Rathmines Town Hall (completed 1899) and the Graduates' Building at Trinity College. He took an interest in historic buildings and was the first to draw serious attention to the architectural and historic importance of the St. Audoen's Church, Dublin's oldest parish church, in 1866. He produced detailed plans of the church for which he won an award from the RIAI, carried out excavations and drew up a paper on the church and its history.
His most significant work in Belfast was St Anne’s Cathedral, completed in 1899.
He was inaugural President of the Royal Society of Ulster Architects, serving from 1901-1903. In addition, he was President of the RIAI, the RSAI and the RHA and held the chair in architecture at the National University of Ireland. He lived in Monkstown, Dublin.