1990 Cottesloe state by-election

The 1990 Cottesloe state by-election was a by-election for the seat of Cottesloe in the Legislative Assembly of Western Australia held on 11 August 1990. It was triggered by the resignation of Bill Hassell (the sitting Liberal member and former leader of the opposition) on 28 June 1990. The Liberal Party retained Cottesloe at the election with an increased majority, with Colin Barnett (an economist) securing 70.26 percent of the two-party-preferred vote. The Labor Party did not field a candidate.