Australian immigration detention facilities comprise a number of different facilities throughout Australia, including the Australian territory of Christmas Island. Such facilities also exist in Papua New Guinea and Nauru, namely the Nauru Regional Processing Centre and the Manus Regional Processing Centre.

The Australian government has a policy and practice of detaining in immigration detention facilities non-citizens not holding a valid visa, suspected of visa violations, illegal entry or unauthorised arrival, and those subject to deportation and removal in immigration detention until a decision is made by the immigration authorities to grant a visa and release them into the community, or to repatriate them to their country of origin/passport. Persons in immigration detention may at any time opt to voluntarily leave Australia for their country of origin, or they may be deported or given a bridging or temporary visa. In 1992, Australia adopted a mandatory detention policy obliging the government to detain all persons entering or being in the country without a valid visa, while their claim to remain in Australia is processed and security and health checks undertaken. Also, at the same time, the law was changed to permit indefinite detention, from the previous limit of 273 days. The policy was instituted by the Keating government in 1992, and was varied by the subsequent Howard, Rudd, Gillard, Abbott, Turnbull, Morrison and Albanese Governments. The policy is regarded as controversial and has been criticised by a number of organisations. In 2004, the High Court of Australia confirmed the constitutionality of indefinite mandatory detention of non-citizens. However, this interpretation was overturned in a landmark decision, NZYQ v Minister for Immigration, in 2023, with the High Court concluding the practice was unlawful and unconstitutional.