The Australian Army, established in March 1901 by amalgamating colonial forces, serves as the nation's principal land warfare component within the Australian Defence Force. Initially composed largely of part-time soldiers, it relied on volunteer expeditionary forces—such as the First Australian Imperial Force (AIF) in World War I—for overseas combat until a standing regular army was formed post-1947 to facilitate its global participation.

Throughout its history, the Army has been involved in numerous major conflicts, including the Second Boer War, both World Wars (with Australian territory only directly attacked during WWII), and the Korean, Vietnam, Afghanistan, and Iraq Wars. Since 1947, it has also been a key participant in many United Nations peacekeeping operations worldwide. Today, its roles extend to multilateral exercises, emergency disaster relief, and humanitarian aid in response to various domestic and international crises.