12th Corps, Twelfth Corps, or XII Corps may refer to:
12th Army Corps (France) XII Corps (Grande Armée), a corps of the Imperial French Army during the Napoleonic Wars XII (1st Royal Saxon) Corps, a unit of the Imperial German Army XII (Royal Saxon) Reserve Corps, a unit of the Imperial German Army XII Corps (India) XII Corps (North Korea) XII Corps (Ottoman Empire) XII Corps (Pakistan) 12th Rifle Corps (Soviet Union) XII Corps (United Kingdom) XII Corps (United States) XII Army Corps (Wehrmacht), a German unit World War II XII Corps (Union Army), a unit in the American Civil War
See also List of military corps by number 12th Army Corps 12th Army (disambiguation) 12th Battalion (disambiguation) 12th Brigade (disambiguation) 12th Division (disambiguation) 12th Group (disambiguation) 12th Regiment (disambiguation) 12 Squadron (disambiguation)