40th Regiment

40th Regiment, 40th Infantry Regiment or 40th Armoured Regiment may refer to:

Infantry regiments

• 40th (2nd Somersetshire) Regiment of Foot, a unit of the United Kingdom Army
• 40th Infantry Regiment (United States), a unit of the American Regular Army.

Armoured regiments

• 40th (The King's) Royal Tank Regiment, a unit of the United Kingdom Army
• 40th/41st Royal Tank Regiment, a unit of the United Kingdom Army

Artillery regiments

• 40th Regiment Royal Artillery, a unit of the United Kingdom Army

Aviation regiments

• 40th Fighter Aviation Regiment, a unit of the Yugoslav Air Force

Communications regiments

• 40 (Ulster) Signal Regiment, a unit of the United Kingdom Army

American Civil War regiments

• 40th Illinois Volunteer Infantry Regiment, a unit of the Union (Northern) Army during the American Civil War
• 40th Iowa Volunteer Infantry Regiment, a unit of the Union (Northern) Army during the American Civil War
• 40th Wisconsin Volunteer Infantry Regiment, a unit of the Union (Northern) Army during the American Civil War
• 40th New York Volunteer Infantry Regiment, a unit of the Union (Northern) Army during the American Civil War