The 18th Battalion was an infantry battalion of the Australian Army. During World War I, the battalion was raised in 1915 as part of the Australian Imperial Force, attached to the 5th Brigade, of the 2nd Division. It was sent initially to Gallipoli, where it suffered a large number of casualties before it was withdrawn from the line and sent to France, where it served at the Western Front as part of the Australian Corps and took part in most of the major battles between 1916 and 1918. The battalion's last engagement of the war was at Montbrehain in October 1918 and it was disbanded in April 1919. After the war, the battalion was re-raised as a part-time force in the Sydney area and remained there during World War II where it served in a garrison role and was disbanded in 1944 without havin