Fourth Army or 4th Army may refer to:
Germany 4th Army (German Empire), a World War I field Army 4th Army (Wehrmacht), a World War II field army 4th Panzer Army
Russia - Soviet Union 4th Army (Russian Empire) 4th Army (RSFSR) 4th Army (Soviet Union) 4th Air Army, Soviet Union and Russia 4th Guards Army, Soviet Union 4th Tank Army, Soviet Union
Others 4th Army (Austria-Hungary) Fourth Army (Bulgaria) Fourth Army (National Revolutionary Army), Republic of China New Fourth Army, Republic of China Fourth Army (France) Fourth Army (Italy) Fourth Army (Japan) Fourth Army (Ottoman Empire) Fourth Army (Romania) Fourth Army (United Kingdom) Fourth United States Army 4th Army (Kingdom of Yugoslavia)
See also IV Corps (disambiguation) 4th Division (disambiguation) 4th Brigade (disambiguation) 4th Regiment (disambiguation) 4th Squadron (disambiguation)