31st Division may refer to:
Infantry divisions 31st Motorized Infantry Division (People's Republic of China) 31st Division (German Empire), Imperial German Army 31st Infantry Division (Wehrmacht) 31st SS Volunteer Grenadier Division, Germany 31st Ashura Division, Iran 31st Infantry Division "Calabria", Italian Army 31st Division (Imperial Japanese Army), Imperial Japanese Army 31st Division (Philippines) 31st Infantry Division (Russian Empire) 31st Guards Airborne Division, Soviet Union 31st Guards Mechanized Division, Soviet Union 31st Guards Motor Rifle Division, Soviet Army, earlier the 31st Guards Rifle Division 31st Rifle Division, Soviet Union 31st Division (United Kingdom), United Kingdom 31st Infantry Division (United States), United States Army 31st Division (Yugoslav Partisans)
Armoured divisions 31st Armoured Division, British India, World War II
Aviation divisions 31st Air Division, United States Air Force
Artillery divisions 31st Artillery Division, People's Republic of China
Naval divisions 31st Corvette Division, Swedish Navy 31st Naval Supply Ships Division, Ukraine
See also List of military divisions by number 31st Army (disambiguation) 31st Group (disambiguation) XXXI Corps (disambiguation) 31st Brigade (disambiguation) 31st Regiment (disambiguation) 31st Battalion (disambiguation) 31st Squadron (disambiguation)