The 2018 South Australian state election to elect members to the 54th Parliament of South Australia was held on 17 March 2018. All 47 seats in the House of Assembly or lower house, whose members were elected at the 2014 election, and 11 of 22 seats in the Legislative Council or upper house, last filled at the 2010 election, were contested. The record-16-year-incumbent Australian Labor Party (SA) government led by Premier Jay Weatherill was seeking a fifth four-year term, but was defeated by the opposition Liberal Party of Australia (SA), led by Opposition Leader Steven Marshall. Nick Xenophon's new SA Best party unsuccessfully sought to obtain the balance of power.

The 2014 South Australian state election elected members to the 53rd Parliament of South Australia on 15 March 2014, to fill all 47 seats in the House of Assembly and 11 of 22 seats in the Legislative Council. The 12-year-incumbent Australian Labor Party (SA) government, led by Premier Jay Weatherill, won its fourth consecutive four-year term in government, a record 16 years of Labor government, defeating the opposition Liberal Party of Australia (SA), led by Opposition Leader Steven Marshall.