18th Brigade may refer to:
Australia 18th Brigade (Australia)
British India 18th (Belgaum) Brigade 18th Indian Infantry Brigade
Japan 18th Independent Mixed Brigade
Russia 18th Guards Motor Rifle Brigade 18th Motor Rifle Brigade
Ukraine 18th Army Aviation Brigade 18th Sloviansk Brigade
United Kingdom 18th Infantry Brigade (United Kingdom) 18th Mounted Brigade 18th Reserve Brigade Artillery units 18th Brigade Royal Field Artillery XVIII Brigade, Royal Horse Artillery (T.F.)
United States 18th Aviation Brigade (United States) 18th Engineer Brigade 18th Field Artillery Brigade 18th Military Police Brigade
Yugoslavia 18th (Croatian) Eastern Bosnian Brigade, an irregular formation of Yugoslav partisans which opposed German forces during World War II
See also 18th Army (disambiguation) XVIII Corps (disambiguation) 18th Division (disambiguation) 18th Regiment (disambiguation) 18th Battalion (disambiguation) 18 Squadron (disambiguation)