Elections were held in the state of Western Australia on 12 March 1921 to elect all 50 members to the Legislative Assembly. The incumbent government, led by Premier James Mitchell of the Nationalist Party and supported by the Country Party and National Labor Party, won a second term in government against the Labor Party opposition, led by Opposition Leader Philip Collier.
At this election Edith Cowan became the first woman elected to any Australian parliament.
 ;templatestyles src="Citation/styles.css"/ ;1 164,688 electors were enrolled to vote at the election, but 6 of the 50 seats were uncontested, with 17,740 electors enrolled in those seats. Of these, 3 were held by Labor, 2 by the Country Party and 1 was held by the National Labor Party.
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