Australians, colloquially known as Aussies, are the citizens, nationals and individuals associated with the country of Australia. This connection may be residential, legal, historical or ethno-cultural. For most Australians, several (or all) of these connections exist and are collectively the source of their being Australian. Australian law does not provide for a racial or ethnic component of nationality, instead relying on citizenship as a legal status.

Since the postwar period, Australia has pursued an official policy of multiculturalism and has the world's eighth-largest immigrant population, with immigrants accounting for 30 percent of the population in 2019.

Between European colonisation in 1788 and the Second World War, the vast majority of settlers and immigrants came from the British Isles (principally England, Ireland and Scotland), although there was significant immigration from China and Germany during the 19th century. Many early settlements were initially penal colonies to house transported convicts. Immigration increased steadily, with an explosion of population in the 1850s following a series of gold rushes. In the decades immediately following the Second World War, Australia received a large wave of immigration from across Europe, with many more immigrants arriving from Southern and Eastern Europe than in previous decades. Since the late 1970s, following the end of the White Australia policy in 1973, a large and continuing wave of immigration to Australia from around the world has continued into the 21st century, with Asia now being the largest source of immigrants. A smaller proportion of Australians are descended from Australia's indigenous peoples, comprising Aboriginal Australians and Torres Strait Islanders.

The development of a distinctive Australian identity and national character began in the 19th century and culminated in the federation of the Australian colonies in 1901. The primary language is Australian English. Australia is home to a diversity of cultures, a result of its history of immigration. Since 1788, Australian culture has primarily been a Western culture strongly influenced by early Anglo-Celtic settlers. As the Asian Australian population continues to expand and flourish as a result of changes in the demographic makeup of immigrants and as there has been increased economic and cultural intercourse with Asian nations, Australia has observed the gradual emergence of a "Eurasian society" within its major urban hubs, blending both Western and Asian material and popular culture within a distinctly Australian context. Other influences include Australian Aboriginal culture, the traditions brought to the country by waves of immigration from around the world, and the culture of the United States. The cultural divergence and evolution that has occurred over the centuries since European settlement has resulted in a distinctive Australian culture.