John Cunningham Martin (April 29, 1880 in Salem, Illinois – January 27, 1952 in Long Beach, California) was an American politician who served as a member of the US House of Representatives from Illinois and as Illinois treasurer. He also served as chairman of the Illinois Emergency Relief Commission 1935 to 1938. He won election as a Democrat to the 76th United States Congress (January 3, 1939 – January 3, 1941), but was not a candidate for renomination in 1940, choosing instead to resume his banking interests.