The Tonkin Ministry was the 25th Ministry of the Government of Western Australia, led by Labor Premier John Tonkin and deputy Herb Graham (Don Taylor replaced Graham following his resignation on 30 May 1973). It commenced on 3 March 1971, eleven days after the Brand–Nalder Ministry, led by Premier David Brand of the Liberal Party, was defeated at the 1971 election. The ministry was followed by the Court–McPharlin Ministry on 8 April 1974 after the Labor Party lost government at the state election held on 31 March.
As was the norm for Labor ministries, the caucus consisting of all parliamentary members elected the ministers, and the Premier then allocated portfolios.