Martin O'Sullivan (died 20 January 1956) was an Irish Labour Party politician. A railway official, he was elected to Dáil Éireann as a Labour Party Teachta Dála (TD) for the Dublin North–West constituency at the 1943 general election. He was re-elected at the 1944 and 1948 general elections. He lost his seat at the 1951 general election. He served as Lord Mayor of Dublin from 1943–45.