HMAS Australia (I84/D84/C01) was a County-class heavy cruiser of the Royal Australian Navy (RAN). One of two Kent-subclass ships ordered for the RAN in 1924, Australia was laid down in Scotland in 1925, and entered service in 1928. Apart from an exchange deployment to the Mediterranean from 1934 to 1936, during which she became involved in the planned British response to the Abyssinia Crisis, Australia operated in local and South-West Pacific waters until World War II began.

The cruiser remained near Australia until mid-1940, when she was deployed for duties in the eastern Atlantic, including hunts for German ships and participation in Operation Menace. During 1941, Australia operated in home and Indian Ocean waters, but was reassigned as flagship of the ANZAC Squadron in early 1942. As part of this force (which was later redesignated Task Force 44, then Task Force 74), Australia operated in support of United States naval and amphibious operations throughout South-East Asia until the start of 1945, including involvement in the battles at the Coral Sea and Savo Island, the amphibious landings at Guadalcanal and Leyte Gulf, and numerous actions during the New Guinea campaign. She was forced to withdraw following a series of kamikaze attacks during the invasion of Lingayen Gulf. The prioritisation of shipyard work in Australia for British Pacific Fleet vessels saw the Australian cruiser sail to England for repairs, where she was at the end of the war.

During the late 1940s, Australia served with the British Commonwealth Occupation Force in Japan, and participated in several port visits to other nations, before being retasked as a training ship in 1950. The cruiser was decommissioned in 1954, and sold for scrapping in 1955.