A by-election for the seat of Balcatta in the Legislative Assembly of Western Australia was held on 28 July 1973. It was triggered by the resignation of Herb Graham, the deputy premier in the Labor government of John Tonkin, on 30 May 1973.
Like the earlier 1971 Ascot by-election, the Balcatta by-election was of great importance to the Labor Party, as a loss would have seen it reduced to minority government. The party retained the seat despite a 16.5-point negative swing, with Brian Burke (a future premier) outpolling the Liberal candidate, Neil Beck, by only 30 votes on the two-party-preferred count. Burke had been behind Beck on first preferences, but passed him after the preferences of the Australia Party candidate were distributed.