Elections were held in the state of Western Australia on 29 September 1917 to elect 50 members to the Western Australian Legislative Assembly. The Nationalist-Country-National Labor coalition, led by Premier Sir Henry Lefroy, retained government against the Labor Party led by Opposition Leader Philip Collier. The election followed a series of major changes in the Western Australian political landscape.

Results

As the political changes were of a nature which make direct comparison meaningless, no vote swings have been included, and seat swings indicated are those caused by the election itself, rather than a comparison with the previous election. The National Liberal grouping was not a party in its own right, but a faction within the Nationalist Party, so the Nationalist Party as a whole held 16 seats—unchanged from before the election—and attracted 34.85% of the vote. Notes: