This article provides a summary of results for elections to the Western Australian Legislative Assembly, the lower house in Western Australia's bicameral state legislative body, the Parliament of Western Australia, which came into being in 1890 when Western Australia achieved responsible self-government. The number of seats has increased over time, from 30 at its first election, to the current total of 57 seats. Western Australian politics were initially non-partisan, with individual Members of Parliament choosing to align either with the Government or the Opposition. This began to change in the 1901 election with the election of six Labor members, and then with Labor attaining outright victory in the 1904 election. By 1911, a rival party to Labor had emerged in the centre-right Liberal Party of Western Australia, which many of the former independents had joined. This entity evolved into the Nationalist Party and eventually into the Liberal Party in 1944.
The chart below shows the information graphically, with the most recent results on the right. It shows the popularity in terms of seats won, of the Australian Labor Party (red) and the Nationalist Party and its predecessors (mid-blue) in the first half of the 20th century, as well as the emergence of the Country Party (green) in 1914, with whom the Nationalists and later the Liberals formed a coalition in order to form government. Two distinct periods were characterised by one party or coalition's dominance—the Labor Party won six of the seven elections between 1924 and 1947, and the Liberal Party (dark blue) in coalition with the Country Party won seven of the eight elections between 1959 and 1983. Occasional internal splits within the Country Party, now known as the Nationals, are also shown on the chart in differing shades of green.