John Olsen, Australian politician, 42nd Premier of South Australia
John Wayne Olsen, AO (born 7 June 1945) is a former Australian politician, diplomat and football commissioner. He was Premier of South Australia between 28 November 1996 and 22 October 2001. He is now President of the Federal Liberal Party, Chairman of the Australian American Association, Chairman of the Adelaide Football Club and Deputy Chairman of the Adelaide Oval Stadium Management Authority.

Olsen was twice the parliamentary leader of the South Australian Division of the Liberal Party of Australia in the South Australian House of Assembly, from 1982 to 1990 and again from 1996 to 2001. He unsuccessfully led the party to both the 1985 election and 1989 election. After the 1989 election he left South Australian parliament to fill a casual vacancy in the Australian Senate. He returned to the South Australian parliament in 1992, but was defeated for the Liberal party leadership by Dean Brown.

However, in 1996, Olsen successfully challenged Brown for the Liberal leadership, and hence became Premier. He led the party to a narrow victory at the 1997 election, and remained Premier until 2001. He was resigned in 2001, after he was found to have misled parliament during the Motorola affair. Olsen is the longest-serving Liberal Party of Australia Premier of South Australia and the fourth-longest-serving Leader of the Opposition.

After politics Olsen worked as a diplomat and political lobbyist. He became the State President of the South Australian Liberal Party in June 2017. He previously held that position from 1976 to 1979. He was appointed an Officer of the Order of Australia in January 2007.