First Army may refer to:

China

  • New 1st Army, Republic of China
  • First Field Army, a Chinese Communist Party unit in the Chinese Civil War
  • 1st Group Army, People's Republic of China

Germany

  • 1st Army (German Empire), a World War I field Army
  • 1st Army (Wehrmacht), a World War II field army
  • 1st Panzer Army
  • 1st Parachute Army (Wehrmacht)

Russia and the Soviet Union

  • First Western Army
  • 1st Army (Russian Empire)
  • 1st Red Banner Army
  • 1st Shock Army
  • 1st Guards Tank Army (Russia)

Others

  • First Allied Airborne Army
  • First Australian Army
  • 1st Army (Austria-Hungary)
  • First Army (United Kingdom)
  • First Army (Bulgaria)
  • First Canadian Army
  • 1st Army (France)
  • First Army (Greece)
  • First Army (Hungary)
  • First Army (Italy)
  • First Army (Japan)
  • First Army (Ottoman Empire)
  • First Polish Army (1920)
  • First Polish Army (1944–1945)
  • First Army (Romania)
  • First Army (Serbia)
  • First Army (Turkey)
  • First Army (United Arab Republic)
  • First United States Army
  • 1st Army (Kingdom of Yugoslavia)
  • 1st Army (Yugoslav Partisans)

See also

  • I Corps (disambiguation)
  • 1st Division (disambiguation)
  • 1st Brigade (disambiguation)
  • 1st Regiment (disambiguation)