1 On 29 March 1939, Aubrey Coverley, the member for Kimberley was appointed as Minister for the North-West in the Willcock Ministry, whilst Emil Nulsen, the member for Kanowna, was appointed Minister for Justice and Minister for Railways. Both were therefore required to resign and contest ministerial by-elections on 5 April 1939, in which both were returned unopposed.
2 On 20 March 1939, the Labor member for Forrest, May Holman, died after a car crash. Her brother, Edward Holman, won the resulting by-election on 20 May 1939—the third family member in a row to hold the seat, as their father, John Holman, had held it from a 1923 by-election until his death in 1925.