121st Brigade
121st Brigade may refer to:
- 121st Brigade (United Kingdom)
- 121st Brigade, Republic of China; see January 28 incident order of battle
- 121st Artillery Brigade, Soviet Union
- 121 (Independent) Infantry Brigade, part of 8th Infantry Division (India)
- 121st High-Power Howitzer Artillery Brigade, part of 5th Shock Army, Soviet Union
- 121st Tank Brigade, part of 65th Army (Soviet Union)
- 121st Territorial Defense Brigade (Ukraine)