121st Regiment

121st Regiment or 121st Infantry Regiment may refer to:

• 121st Regiment of Foot (disambiguation), several units
• 121st Regiment (Xinjiang Production and Construction Corps), People's Republic of China
• 121st Infantry Regiment (France)
• 121st Anti-aircraft Artillery Regiment "Ravenna", Italy
• 121st Infantry Regiment "Macerata", Italy
• 121st Infantry Regiment (United States)
• 121st Field Artillery Regiment (United States)