The 27th Battalion was an infantry battalion of the Australian Army. It was initially raised in 1915 as part of the First Australian Imperial Force for service during World War I. During the conflict, the battalion saw action briefly at Gallipoli before later fighting on the Western Front between 1916 and 1918. It was disbanded in 1919, but was re-raised in 1921 as part of the Citizens Force, which later became the "Militia". During World War II the battalion was used mainly in a garrison role until the last year of the war when it was committed to the fighting against the Japanese during the Bougainville campaign. Following the end of hostilities it was disbanded in May 1946. Between 1948 and 1965 the battalion was re-raised and disbanded a number of times before eventually becoming part