Elections were held in the colony of South Australia on 29 April 1899, except for Albert, where the incumbent members were elected unopposed on 12 April, and Northern Territory, which voted on 6 May. All 54 seats in the South Australian House of Assembly were up for election. The incumbent liberal government led by Premier of South Australia Charles Kingston in an informal coalition United Labor Party (ULP) led by Lee Batchelor defeated the conservative opposition led by Leader of the Opposition John Downer. Each district elected multiple members, with voters casting multiple votes. Although the conservatives won more seats, the liberal government retained power until later that year, when new conservative leader Vaiben Louis Solomon forced the government to resign, but only held office fo