13th Division
- 13 Squadron (disambiguation)
- 13th (Western) Division
- 13th Air Defense Division
- 13th Airborne Division (United States)
- 13th Armored Division (United States)
- 13th Army (disambiguation)
- 13th Army Division
- 13th Brigade (disambiguation)
- 13th Division (German Empire)
- 13th Division (Imperial Japanese Army)
- 13th Division (North Korea)
- 13th Division (People's Republic of China)
- 13th Division (Syrian rebel group)
- 13th Division (United States)
- 13th Group (disambiguation)
- 13th Guards Airborne Division
- 13th Guards Cavalry Division
- 13th Guards Rifle Division
- 13th Guards Tank Division
- 13th Infantry Division (Greece)
- 13th Infantry Division (Poland)
- 13th Infantry Division (United Kingdom)
- 13th Infantry Division Re
- 13th Panzer Division (Wehrmacht)
- 13th Panzergrenadier Division (Bundeswehr)
- 13th Regiment (disambiguation)
- 13th Reserve Division (German Empire)
- 13th Rifle Division (Soviet Union)
- 13th Strategic Missile Division
- 13th Tank Division (Czechoslovakia)
- 13th Tank Division (People's Republic of China)
- 13th Waffen Mountain Division of the SS Handschar (1st Croatian)