Military history of Australia during World War II

Australia entered World War II on 3 September 1939, following the government's acceptance of the United Kingdom's declaration of war on Nazi Germany. Australia later entered into a state of war with other members of the Axis powers, including the Kingdom of Italy on 11 June 1940,^[1] and the Empire of Japan on 9 December 1941.^[2] By the end of the war, almost one million Australians had served in the armed forces, whose military units fought primarily in the European theatre, North African campaign, and the South West Pacific theatre. In addition, Australia came under direct attack for the first time in its post-colonial history. Its casualties from enemy action during the war were 27,073 killed and 23,477 wounded.^[3] Many more suffered from tropical disease, hunger, and harsh conditions in captivity; of the 21,467 Australian prisoners taken by the Japanese, only 14,000 survived.

Australian Army units were gradually withdrawn from the Mediterranean and Europe following the outbreak of war with Japan. However, Royal Australian Air Force and Royal Australian Navy units and personnel continued to take part in the war against Germany and Italy. From 1942 until early 1944, Australian forces played a key role in the Pacific War, making up the majority of Allied strength throughout much of the fighting in the South West Pacific theatre. While the military was largely relegated to subsidiary fronts from mid-1944, it continued offensive operations against the Japanese until the war ended.

World War II contributed to major changes in the nation's economy, military and foreign policy. The war accelerated the process of industrialisation, led to the development of a larger peacetime military and began the process with which Australia shifted the focus of its foreign policy from Britain to the United States. The final effects of the war also contributed to the development of a more diverse and cosmopolitan Australian society.