John Joseph Cahill (21 January 189122 October 1959), also known as Joe Cahill or J. J. Cahill, was a long-serving New South Wales politician, railway worker, trade unionist and Labor Party Premier of New South Wales from 1952 to his death in 1959. Born the son of Irish migrants in Redfern, New South Wales, Cahill worked for the New South Wales Government Railways from the age of 16 before joining the Australian Labor Party. Being a prominent unionist organiser, including being dismissed for his role in the 1917 general strike, Cahill was eventually elected to the Parliament of New South Wales for St George in 1925.