Second Army
- 2nd Army (Austria-Hungary)
- 2nd Army (German Empire)
- 2nd Army (Kingdom of Yugoslavia)
- 2nd Army (RSFSR)
- 2nd Army (Russian Empire)
- 2nd Army (Wehrmacht)
- 2nd Brigade (disambiguation)
- 2nd Division (disambiguation)
- 2nd Guards Army
- 2nd Guards Tank Army
- 2nd Panzer Army
- 2nd Red Banner Army
- 2nd Regiment (disambiguation)
- 2nd Ukrainian Soviet Army
- II Army (Argentina)
- II Corps (disambiguation)
- Second Army (Australia)
- Second Army (Bulgaria)
- Second Army (Egypt)
- Second Army (France)
- Second Army (Home Forces)
- Second Army (Hungary)
- Second Army (Italy)
- Second Army (Japan)
- Second Army (Ottoman Empire)
- Second Army (Poland)
- Second Army (Romania)
- Second Army (Serbia)
- Second Army (Turkey)
- Second Army (United Kingdom)
- Second Army Corps (Spanish-American War)
- Second United States Army
- Second Western Army