100th Brigade may refer to:
Germany 100th Brigade (Wehrmacht) 100th Panzer Brigade
India 100th Indian Infantry Brigade
Russia 100th Separate Guards Reconnaissance Brigade 100th Separate Guards Motorized Rifle Brigade, known as the 110th Brigade since 2023
Soviet Union 100th Kazakh Rifle Brigade
Ukraine 100th Mechanized Brigade
United Kingdom 100th Anti-Aircraft Brigade 100th Brigade (United Kingdom) 100th Brigade, Royal Field Artillery, a British Army unit during World War I 100th (Worcestershire and Oxfordshire Yeomanry) Brigade, Royal Field Artillery, a British Army unit after World War I
United States 100th Missile Defense Brigade
See also 100th Division (disambiguation) 100th Regiment (disambiguation)