1st Division or First Division may refer to:
Military
Airborne divisions
1st Parachute Division (Germany)
1st Airborne Division (United Kingdom)
1st Airmobile Division (Ukraine)
1st Guards Airborne Division
Armoured divisions
1st Armoured Division (Australia)
1st Canadian Armoured Division (subsequently renamed the 5th Canadian Division)
1st Armored Division (People's Republic of China)
1st Armored Division (France)
1st Light Mechanized Division (France)
1st Panzer Division (Bundeswehr), (West) Germany
1st Panzer Division (Wehrmacht), Nazi Germany
Fallschirm-Panzer Division 1 Hermann Göring, Nazi Germany
1st Armoured Division (India)
1st Tank Division (Imperial Japanese Army)
1st Armoured Division (Poland)
1st Mechanised Division (Poland)
1st Mechanized Division (Soviet Union)
1st Armoured Division (United Kingdom)
1st Armored Division (United States)
1st Armoured Division (Syria)
1st Guards Mechanized Corps (Soviet Union)
1st Tank Division (Soviet Union)
1st Armored Brigade (People's Republic of China), formerly the 1st Tank Division, then 1st Armored Division
Artillery divisions
1st Anti-Aircraft Division (Japan)
1st Anti-Aircraft Artillery Division (Soviet Union)
1st Anti-Aircraft Division (United Kingdom)
1st Flak Division
Aviation divisions
1st Fighter Division (China)
Cavalry divisions
1st Light Cavalry Division (France)
1st Foot Cavalry Division (France)
1st Cavalry Division (German Empire)
1st Cavalry Division (Reichswehr), Weimar Republic, Germany
1st Cavalry Division (Wehrmacht), Nazi Germany
1st Light Division (Germany)
1st Indian Cavalry Division, British Indian Army during World War I
1st Cavalry Division "Eugenio di Savoia", Royal Italian Army
1st Cavalry Division (Poland)
1st Guard Cavalry Division (Russian Empire)
1st Cavalry Division (Soviet Union)
1st Cavalry Division (United Kingdom)
1st Mounted Division (United Kingdom)
1st Cavalry Division (United States)
Infantry divisions
1st Guards Infantry Division ()