Martin O'Sullivan (1891 – 20 January 1956) was an Irish Labour Party politician. He was born in 1891 in Ennistymon, County Clare. He was educated locally, and joined the Midland Great Western Railway as a clerk and worked in Sligo and Cavan before his appointment as station master at Recess, County Galway. After the amalgamation of the Midland Great Western and Great Southern railways, he was transferred to Dublin and later became chief paymaster at Inchicore railway works for Great Southern and Western Railway.