This is a list of armies arranged by ordinal numeral.
First Army First Allied Airborne Army First Army (Australia) First Army (Austria-Hungary) First Army (Bulgaria) First Canadian Army New 1st Army (Republic of China) 1st Army (Czechoslovakia) First Army (France) 1st Army (German Empire), a World War I field army 1st Army (Wehrmacht), a World War II field army 1st Panzer Army (Germany) 1st Parachute Army (Germany) First Army (Greece) First Army (Hungary) First Army (Italy) First Area Army First Army (Ottoman Empire) First Polish Army (1920) First Polish Army (1944–45) 1st Army (South Korea) First Army (Romania) 1st Army (Russian Empire) First Army (Serbia) 1st Red Banner Army (Soviet Union) First Army (Turkey) First Army (United Kingdom) First United States Army 1st Army (Kingdom of Yugoslavia) 1st Army (Yugoslav Partisans)
Second Army Second Army (Australia) Second Army (Austria-Hungary) Second Army (Bulgaria) Second Army (Egypt) Second Army (France) 2nd Army (German Empire), a World War I field army 2nd Army (Wehrmacht), a World War II field army 2nd Panzer Army (Germany) Second Army (Hungary) Second Army (Italy) Second Army (Japan) Second Army (Ottoman Empire) Second Army (Poland)
2nd Army (Russian Empire) Second Army (Serbia) 2nd Red Banner Army (Soviet Union) Second Army (Turkey) Second United States Army Second Army (United Kingdom) 2nd Army (Kingdom of Yugoslavia) 2nd Army (Yugoslav Partisans)
Third Army 3rd Army (Austria-Hungary) Third Army (Bulgaria) Third Army (Egypt) Third Army (France) 3rd Army (German Empire), a World War I field army 3rd Army (Wehrmacht), a World War II field army 3rd Panzer Army (Germany) 3rd Army (East Germany) Third Army (Ottoman Empire) Third Army (Italy) Third Army (Romania) Third Army (Serbia) 3rd Army (Russian Empire) 3rd Army (Soviet Union) 3rd Guards Army (Soviet Union) 3rd Guards Tank Army (Soviet Union) 3rd Shock Army (Soviet Union) 3rd Air Army (Soviet Union) 3rd Army (South Korea) Third Army (Turkey) Third Army (United Kingdom) Third United States Army 3rd Army (Kingdom of Yugoslavia) 3rd Army (Yugoslav Partisans)
Fourth Army 4th Army (Austria-Hungary) Fourth Army (Bulgaria) Fourth Army (National Revolutionary Army) (Republic of China) New Fourth Army (Republic of China) Fourth Army (France) 4th Army (German Empire), a World War I field army 4th Army (Wehrmacht), a World War II field army 4th Panzer Army (Germany) Fourth Army (Ottoman Empire) Fourth Army (Italy) Fourth Army (Romania) 4th Army (Russian Empire) 4th Army (Soviet Union) 4th Air Army (Soviet Union and later Russian Federation) 4th Guards Army (Soviet Union) 20th Guards Army (originally designated as "Fourth Tank Army") (Soviet Union) Fourth Army (United Kingdom) Fourth United States Army 4th Army (Kingdom of Yugoslavia) 4th Army (Yugoslav Partisans)
Fifth Army Fifth Army (Austria-Hungary) Fifth Army (Bulgaria) Fifth Army (France) 5th Army (German Empire), a World War I field army 5th Army (Wehrmacht), a World War II field army 5th Panzer Army (Germany) Fifth Army (Japan) Fifth Army (Ottoman Empire) Fifth Army (Italy) 5th Army (Russian Empire) 5th Army (Soviet Union) Fifth Army (United Kingdom) Fifth United States Army, another name for United States Army North 5th Army (Kingdom of Yugoslavia)
Sixth Army Sixth Army (Austria-Hungary) Sixth Army (France) 6th Army (German Empire), a World War I field army 6th Army (Wehrmacht), a World War II field army 6th Panzer Army (Germany) Sixth Army (Japan) Sixth Army (Ottoman Empire) Sixth Army (Italy) 6th Army (Russian Empire) 6th Army (Soviet Union) Sixth United States Army Sixth United States Army Group - one of only two United States army groups ever activated. 6th Army (Kingdom of Yugoslavia)
Seventh Army 7th Army (Austria-Hungary) Seventh Army (France) 7th Army (German Empire), a World War I field army 7th Army (Wehrmacht), a World War II field army Seventh Army (Ottoman Empire) Seventh Army (Italy) 7th Army (Russian Empire) 7th Army (Soviet Union) Seventh United States Army, another name for United States Army Europe 7th Army (Kingdom of Yugoslavia)
Eighth Army
Eighth Route Army, a Chinese Communist force that fought against the Japanese during World War II Eighth Army (France) 8th Army (German Empire), a World War I field army 8th Army (Wehrmacht), a World War II field army Japanese Eighth Area Army Ottoman Eighth Army Eighth Army (Italy), during World War II another name for the Italian Army in Russia Eighth Army (United Kingdom) Eighth United States Army 8th Army (Russian Empire) 8th Army (Soviet Union) 8th Guards Army (Russia)
Ninth Army Ninth Army (France), a field army during World War I and World War II 9th Army (German Empire), a World War I field army 9th Army (Wehrmacht), a World War II field army Ninth Army (Ottoman Empire), a World War I field army Ninth Army (Italy) 9th Army (Russian Empire), a World War I field army 9th Army (Soviet Union), a field army active from 1939–43 and then after the war from 1966-1989 Ninth Army (United Kingdom), a British Army formation during World War II Ninth United States Army, used in Northwest Europe in 1944 and 1945
Tenth Army 10th Army (Austria-Hungary) Tenth Army (France) 10th Army (German Empire), a World War I field army 10th Army (Wehrmacht), a World War II field army Tenth Army (Japan) Tenth Army (Italy) 10th Army (Russian Empire) 10th Army (Soviet Union) Tenth Army (United Kingdom) 10th Guards Army (Soviet Union) Tenth United States Army
Eleventh Army 11th Army (German Empire), a World War I field army 11th Army (Wehrmacht), a World War II field army 11th SS Panzer Army Eleventh Army (Japan) Eleventh Army (Italy) 11th Air Army (Russia) 11th Army (Russian Empire) 11th Army (Soviet Union) 11th Army Group (United Kingdom)
Twelfth Army 12th Army (German Empire), a World War I field army 12th Army (Wehrmacht), a World War II field army Twelfth Army (Japan) 12th Army (Russian Empire) 12th Army (Soviet Union) Twelfth Army (United Kingdom) Twelfth Army (Italy)
Thirteenth Army Thirteenth Army (Japan) Japanese Thirteenth Area Army 13th Army (Russian Empire)
Fourteenth Army 14th Army (German Empire), a World War I field army 14th Army (Wehrmacht), a World War II field army Japanese Fourteenth Area Army 14th Army (Soviet Union) 14th Guards Army (Soviet Union) Fourteenth Army (United Kingdom) Fourteenth United States Army, a World War II 'phantom' force
Fifteenth Army 15th Army (Wehrmacht), a formation of the German Army during World War II Fifteenth Army (Japan), a formation of the Imperial Japanese Army during World War II Japanese Fifteenth Area Army, a formation of the Imperial Japanese Army during World War II 15th Army Group, a combined formation of the United Kingdom and United States armies during World War II Fifteenth United States Army, a formation of the United States Army during World War II
Sixteenth Army 16th Army (Wehrmacht), a unit of the German Army in World War II 11th Guards Army (16th Army, Soviet Union), a unit of the Soviet Army from World War II through the Cold War Western Army (Russia) (16th Soviet Army), a unit of the Soviet Army during World War I 16th Army (People's Republic of China), a unit of People's Republic of China which still active right now.
Seventeenth Army 17th Army (German Empire), a World War I field Army 17th Army (Wehrmacht), a World War II field army Seventeenth Army (Japan) Japanese Seventeenth Area Army during World War II (see List of Armies of the Japanese Army) 17th Army (Soviet Union)
Eighteenth Army 18th Army (German Empire), a World War I field Army 18th Army (Wehrmacht), a World War II field army 18th Army (Soviet Union) Eighteenth Army (Japan)
Nineteenth Army 19th Army (German Empire), a World War I field Army 19th Army (Wehrmacht), a World War II field army Nineteenth Army (Japan) 19th Army (Soviet Union)
Twentieth Army Twentieth Army (Japan) 20th Group Army - People's Liberation Army 20th Guards Army - Soviet Union and Russia 20th Army (Soviet Union) 20th Mountain Army (Wehrmacht)
Twenty first Army 21st Army (Wehrmacht) 21st Army Group - a World War II British army group, consisting mainly of British and Commonwealth troops
See also Lists of armies List of countries by number of military and paramilitary personnel