Paul Joseph James Martin (June 23, 1903-September 14, 1992) was a noted Canadian politician.

Born in Ottawa, Ontario to a franco-ontarian family, he soon moved to Windsor, Ontario. A member of the Liberal Party of Canada, he was first elected to the House of Commons in 1935 and entered cabinet in 1945. He went on to serve as a noted member of four Prime Ministers' cabinets: those of William Lyon Mackenzie King, Louis St. Laurent, Lester B. Pearson and Pierre Trudeau.

Martin was viewed as one of the most left-wing members of the Liberal cabinet, and as Minister of National Health and Welfare he played an important role in the fight against polio and overseeing the creation of Medicare in Canada. He ran for the Liberal leadership three times, in 1948, 1958, and 1968, but lost all three times. Trudeau appointed him to the Senate in 1969, where he served as Government Leader, and in 1974 he was appointed High Commissioner to the United Kingdom.

Paul Martin, Sr. is the father of Paul Martin, Jr another noted Liberal cabinet minister, who in 2003 became the 21st Prime Minister of Canada.