The state election for the 51st Parliament of South Australia was held in the Australian state of South Australia on 18 March 2006 to elect all members of the South Australian House of Assembly and 11 members of the South Australian Legislative Council. The election was conducted by the independent State Electoral Office.

The Parliament of South Australia is the bicameral legislature of the Australian state of South Australia. It consists of the 47-seat House of Assembly and the 22-seat Legislative Council. General elections are held every 4 years, with all of the lower house and half of the upper house filled at each election. It follows a Westminster system of parliamentary government with the executive branch required to both sit in parliament and hold the confidence of the House of Assembly. The parliament is based at Parliament House on North Terrace in the state capital of Adelaide.