This is a list of members of the South Australian House of Assembly from 1918 to 1921, as elected at the 1918 state election:
1 Alexandra Liberal MHA
Archibald Peake died on 6 April 1920. Liberal candidate
Herbert Hudd won the resulting by-election on 12 June.
2 East Torrens MHA
John Albert Southwood resigned from the
National Party in 1920 and served out his term as an independent Labor member.
3 Murray Liberal MHA Herbert Angas Parsons resigned on 5 January 1921. No by-election was held due to the proximity of the 1921 state election.
4 Sturt Liberal MHA
Edward Vardon resigned on 15 February 1921 in order to nominate for a casual vacancy in the
Australian Senate. No by-election was held due to the proximity of the 1921 state election.