A by-election for the seat of Greenough in the Legislative Assembly of Western Australia was held on 1 November 1975.
It was triggered by the resignation of Sir David Brand (the sitting Liberal member and a former premier) on 21 August 1975.
The Liberal Party retained Greenough at the by-election, with its candidate, Reg Tubby, winning 57.3 percent of the two-candidate-preferred (2CP) vote.
He was party leader from 1957 to 1973 and premier from 1959 to 1971, setting records for length of service in both positions.
[3] The by-election occurred in the final days of the 1975 Australian constitutional crisis, which culminated with the dismissal of Prime Minister Gough Whitlam (an unpopular figure in Western Australia) on 11 November.