In military terms, 51st Division or 51st Infantry Division may refer to:
Infantry divisions 51st Division (1st Formation) (People's Republic of China), 1949–1952 51st Reserve Division, German Empire 51st Infantry Division "Siena", Kingdom of Italy 51st Division (Imperial Japanese Army) 51st Division (Philippines) 51st Infantry Division (Russian Empire) 51st Infantry Division (South Korea) 51st Guards Motor Rifle Division, Soviet Union 51st Guards Rifle Division, Soviet Union 51st Rifle Division, Soviet Union 51st (Highland) Division, United Kingdom 51st Infantry Division (United States)
Other divisions 51st Air Defence Division, Soviet Union 51st Guards Artillery Division, Soviet Union 51st Tank Division, Soviet Union
See also 51st (Highland) Division War Memorial (disambiguation) Reel of the 51st Highlanders List of military divisions by number 51st Army (disambiguation) 51st Brigade (disambiguation) 51st Regiment (disambiguation) 51st Squadron (disambiguation)