Western Australia's history dates back over 4 billion years, with the region’s geological history marked by the formation of ancient zircons around 4.4 billion years ago. The earliest known life on land, stromatolites formed by microbes, appeared about 3.48 billion years ago. The first human inhabitants of Australia arrived more than 50,000 years ago, establishing long-standing Indigenous communities in Western Australia long before European explorers began to chart its coast in the early 17th century.

Dutch explorer Dirk Hartog’s expedition in 1616 marked the first European landing in Western Australia, at Cape Inscription on Dirk Hartog Island. For much of the 17th century, Dutch and British navigators continued to explore the coast, though it was often by accident due to storms and navigational errors. By the late 18th century, British and French explorers had begun more deliberate mapping of the region, and in 1800, the Baudin expedition included a thorough survey of Western Australia, ultimately producing the first map to feature the entire Australian continent.

The modern history of Western Australia began with the establishment of the Swan River Colony in 1829, spearheaded by Captain James Stirling. Initially a small settlement, it grew slowly, with major growth only occurring after significant gold discoveries in the 1890s around Kalgoorlie. In 1887, Western Australia gained self-governance, and by 1890, a new constitution allowed for local self-rule. John Forrest became the colony's first Premier, leading the charge for the colony's future economic development, including the construction of a crucial water pipeline from Perth to Kalgoorlie. This Goldfields Water Supply Scheme, completed in 1903, was instrumental in supporting the booming population around the goldfields.

The push for federation culminated on 1 January 1901, when Western Australia officially became one of the founding states of the Commonwealth of Australia.