I Corps
- 1 Squadron (disambiguation)
- 1st Airborne Corps (Soviet Union)
- 1st Army (disambiguation)
- 1st Army Corps (Armed Forces of South Russia)
- 1st Army Corps (France)
- 1st Army Corps (Russian Empire)
- 1st Army Corps (Soviet Union)
- 1st Army Corps (disambiguation)
- 1st Assault Aviation Corps
- 1st Brigade (disambiguation)
- 1st Cavalry Corps (Russian Empire)
- 1st Corps (Syria)
- 1st Corps (Vietnam People's Army)
- 1st Corps (Yugoslav Partisans)
- 1st Division (disambiguation)
- 1st Guards Assault Aviation Corps
- 1st Guards Mechanized Corps (Soviet Union)
- 1st Regiment (disambiguation)
- 1st Rifle Corps
- 1st Suffolk Artillery Volunteer Corps
- 1st Territorial Army Corps (Romania)
- First Army Corps (Spanish-American War)
- First Corps, Army of Northern Virginia
- First Corps, Army of Tennessee
- I ANZAC Corps
- I Airborne Corps (United Kingdom)
- I Amphibious Corps
- I Armored Corps (United States)
- I Army Corps (Greece)
- I Army Corps (Wehrmacht)
- I Canadian Corps
- I Cavalry Corps (German Empire)
- I Cavalry Corps (Grande Armée)
- I Corps (Australia)
- I Corps (Belgium)
- I Corps (Bosnia and Herzegovina)
- I Corps (British India)
- I Corps (Continuation War)
- I Corps (Czechoslovakia)
- I Corps (German Empire)
- I Corps (Grande Armée)
- I Corps (India)
- I Corps (North Korea)
- I Corps (Ottoman Empire)
- I Corps (Pakistan)
- I Corps (South Korea)
- I Corps (South Vietnam)
- I Corps (Sri Lanka)
- I Corps (Union Army)
- I Corps (United Kingdom)
- I Corps (United States)
- I Corps (Winter War)
- I Field Force, Vietnam
- I Reserve Corps (German Empire)
- I Royal Bavarian Corps
- I Royal Bavarian Reserve Corps
- I SS Panzer Corps
- List of military corps by number
- Polish I Corps (disambiguation)