William Davin (19 February 1890 – 1 March 1956) was an Irish Labour Party politician who served as a Teachta Dála (TD) for over thirty years. He was also a station-master. His first candidacy for public office was at the 1922 general election, when he stood as a Labour Party candidate in the Leix–Offaly constituency. He was returned to the 3rd Dáil, and was re-elected at each successive general election until his death in office in 1956. Following his death, a by-election was held on 30 April 1956 which was won by the Fianna Fáil candidate Kieran Egan.