Fifth Army
Fifth Army may refer to:
Germany
- 5th Army (German Empire), a World War I field Army
 - 5th Army (Wehrmacht), a World War II field army
 - 5th Panzer Army
 - 5th Army (GDR), a Warsaw Pact field army in the Cold War to be activated in case of a war with NATO
 
Russia/USSR
- 5th Army (Russian Empire)
 - 5th Army (RSFSR)
 - 5th Army (Soviet Union)
 - 5th Combined Arms Army (Russian Federation)
 
Others
- 5th Army (Austria-Hungary)
 - Fifth Army (Bulgaria)
 - Fifth Army (Nationalist China), see 88th Division (National Revolutionary Army)
 - Fifth Army (France)
 - Fifth Army (Japan)
 - Fifth Army (Ottoman Empire)
 - Fifth Army (United Kingdom)
 - Fifth United States Army
 - Fifth Army (Italy)
 - 5th Army (Kingdom of Yugoslavia)
 - Special Frontier Force of India, during the Indo-Pakistani War of 1971