The 4th Battalion was an infantry battalion of the Australian Army. Originally raised as part of the First Australian Imperial Force during the First World War, the battalion formed part of the 1st Brigade, attached to the 1st Division. During the war the battalion fought at Gallipoli and in the trenches on the Western Front, before being disbanded in 1919. In 1921, the battalion was re-raised as a militia unit and designated as the "4th Battalion (Australian Rifles)", adopting the designation of the Australian Rifles militia unit from which many of the battalion's recruits had come during the war. In 1930, the battalion was amalgamated with the 3rd Battalion (Werriwa Regiment) and they remained linked until 1936, when they were delinked.
During the Second World War, the 4th Battalion formed part of the 8th Brigade. Initially the battalion was used as garrison troops in Australia, serving in Western Australia, in early 1944 they were deployed to New Guinea as part of the 5th Division, where they participated in the Huon Peninsula and Aitape–Wewak campaigns, before returning to Australia in early 1946 and were subsequently disbanded.