Jean Isabel Melzer (née McLeod); 7 February 1926 – 18 June 2013) was an Australian politician and activist. She was a Senator for Victoria from 1974 to 1981, representing the Australian Labor Party (ALP). A long-time supporter of the anti-war and anti-nuclear movements, she left the party in 1984 over its failure to ban uranium mining and stood unsuccessfully for the Nuclear Disarmament Party at the 1984 federal election.