The prehistory of Australia is the period between the first human habitation of the Australian continent and the colonization of Australia in 1788, which marks the start of consistent documentation of Australia. This period is estimated to have lasted between 40,000 and 60,000 years, or longer. This era is referred as prehistory rather than history because there was no consistent written documentation of human events european dating in australia 1788. As no metal technology was developed, the whole period falls into the Stone Age.

The earliest evidence of humans in Australia is at least 65,000 years old. There is considerable discussion among archeologists as to the route taken by the first migrants to Australia, widely taken to be ancestors of the modern Aborigines. Migration took place during the closing stages of the Pleistocene, when sea levels were much lower than they are today. Scott Cane wrote in 2013 that the first wave may have been prompted by the eruption of Toba and if they arrived around 70,000 years ago could have crossed the water from Timor, when the sea level was low – but if they came later, around 50,000 years ago, a more likely route would be through the Moluccas to New Guinea. The minimum widely accepted timeframe for the arrival of humans in Australia is placed at least 40,000 years ago. Many sites dating from this time period have been excavated. In Arnhem Land the Malakunanja II rock shelter has been dated to around 65,000 years old.

Radiocarbon dating suggests that they lived in and around Sydney for at least 30,000 years. Archaeological evidence indicates human habitation at the upper Swan River, Western Australia by about 40,000 years ago. Tasmania, which was connected to the continent by a land bridge, was inhabited at least 30,000 years ago. Charles Dortch has identified chert and calcrete flake stone tools, found at Rottnest Island in Western Australia, as possibly dating to at least 50,000 years ago. The sharing of animal and plant species between Australia-New Guinea and nearby Indonesian islands is another consequence of the early land bridges, which closed when sea levels rose with the end of the last glacial period. It is unknown how many populations settled in Australia prior to European colonisation.