Jack Mortimer (1913 – 8 February 1973) was an Australian politician. He received a primary education before becoming a farmer in South Australia. He served in the military 1942-1946 and returned as a waterside worker in Port Lincoln. In 1963, he was elected to the Australian House of Representatives as the Labor member for Grey. He held the seat until his defeat in 1966, after which he became a businessman in Port Lincoln. Mortimer died in 1973.