James Luke Cavanagh (21 June 1913 – 19 August 1990) was an Australian politician and government minister. Cavanagh was born in Rosewater, South Australia and educated at the Dominican School in North Adelaide. He left school at 14 to work as a plasterer. He became an active member of the pacifist League against War and Fascism and continued to work as a plasterer during World War II. He was the Secretary of the Plasterers Society of South Australia from 1945 to 1962.