515th

515th may refer to:


 * 515th Air Defense Group, disbanded United States Air Force (USAF) organization
 * 515th Air Mobility Operations Wing (515 AMOW), part of Air Mobility Command, stationed at Hickam Air Force Base, Hawaii
 * 515th Bombardment Squadron, inactive United States Air Force unit
 * 515th Parachute Infantry Regiment (United States), Regiment of the US Army during the Second World War
 * 515th Strategic Fighter Squadron, inactive United States Air Force unit