Martin Leslie James Hamilton-Smith (born 1 December 1953) is a former Australian politician who represented the South Australian House of Assembly seat of Waite from the 1997 election until his retirement in 2018.
First elected as a candidate for the Liberal Party, Hamilton-Smith was the state parliamentary leader of the Liberal Party and the Leader of the Opposition in South Australia from 2007 to 2009, and a Minister in the Kerin Liberal government from 2001 to 2002.
He became an independent two months after the 2014 election.
He served as the Minister for Investment and Trade, Minister for Defence Industries and Minister for Veterans’ Affairs in the Weatherill Labor cabinet from May 2014 until January 2018 and Minister for Space Industries and Minister for Health Industries from September 2017 until January 2018.
Hamilton-Smith announced on 6 January 2018 that he would not seek re-election in the 2018 election.