This is a list of members of the Western Australian Legislative Assembly between the 1956 election and the 1959 election, together known as the 22nd Parliament.
- 1 On 17 December 1957, the Labor member for Warren, Ernest Hoar, resigned to take up an appointment as Agent-General for Western Australia in London. Labor candidate Joseph Rowberry won the resulting by-election on 25 January 1958.
- 2 On 11 March 1958, the Labor member for Pilbara, Alec Rodoreda, died. Labor candidate Arthur Bickerton was elected unopposed on 24 April 1958.
- 3 On 29 July 1958, the Country member for Moore, John Ackland, died. Country candidate Edgar Lewis won the resulting by-election on 20 September 1958.