First Army
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)