18th Battalion may refer to:
18th Battalion (Australia), a unit of the Australian Army 1915–1944 2/18th Australian Infantry Battalion, a unit of the Australian Army 1940–1945 18th Battalion (Western Ontario), CEF, a unit of the Canadian Expeditionary Force 1914–1917 18th Logistics Battalion, a unit of the Belgian Army 18th Battalion (New Zealand), a unit of the New Zealand Army 1939–1945
See also XVIII Corps (disambiguation) 18th Division (disambiguation) 18th Brigade (disambiguation) 18th Regiment (disambiguation) 18 Squadron (disambiguation)