Fifteenth Army

15th Army or Fifteenth Army may refer to:


 * 15th Army (Wehrmacht), a formation of the German Army during World War II
 * Fifteenth Army (Japan), a formation of the Imperial Japanese Army during World War II
 * Japanese Fifteenth Area Army, a formation of the Imperial Japanese Army during World War II
 * 15th Army (People's Republic of China), former name of the Chinese People's Liberation Army's 15th Airborne Corps
 * 15th Army (RSFSR)
 * 15th Army (Soviet Union)
 * 15th Army Group, a combined formation of the United Kingdom and United States armies during World War II
 * Fifteenth United States Army, a formation of the United States Army during World War II