1st Regiment

• 1 Regiment Army Air Corps
• 1 Regiment RLC
• 1st (1st East Prussian) Grenadiers "Crown Prince"
• 1st (Emperor Alexander) Guards Grenadiers
• 1st (Royal) Regiment of Foot
• 1st Air Reconnaissance Regiment
• 1st Cavalry Regiment (disambiguation)
• 1st Division (disambiguation)
• 1st Evzone Regiment
• 1st Fighter Regiment
• 1st Foot Guards (German Empire)
• 1st Infantry Regiment (France)
• 1st Infantry Regiment (Greece)
• 1st Infantry Regiment (Thailand)
• 1st Infantry Regiment (United States)
• 1st King's Immemorial Infantry Regiment
• 1st Marine Infantry Regiment
• 1st Marine Regiment (United States)
• 1st Raider Regiment (Greece)
• 1st Regiment Greek Light Infantry
• 1st Regiment of Foot Guards
• 1st Regiment, Royal Australian Artillery
• 1st Serres Regiment
• 1st Training Aviation Regiment
• 1st Transport Aviation Regiment
• 1st Yugoslav Fighter Regiment
• 3rd Special Forces Division (Greece)
• Durban Light Infantry
• First Regiment Massachusetts Volunteer Infantry
• Jäger Regiment 1 (Bundeswehr)
• SS Fortress Regiment 1