Sir John McEwen (29 March 1900 – 20 November 1980) was the 18th Prime Minister of Australia. He was leader of the Country Party when Harold Holt disappeared in 1967, and so was appointed Prime Minister until the Liberal Party elected a new leader. The Party elected John Gorton as the leader, and Gorton took over as Prime Minister on 10 January 1968. McEwen then served as Deputy Prime Minister until 1971.