109th Regiment may refer to:
109th Regiment of Foot (disambiguation), British Army regiments 109th Infantry Regiment (United States) 109th Field Artillery Regiment 109th Regiment Royal Armoured Corps 109th Bomber Aviation Regiment 109th Field Regiment, Royal Artillery 109th (Royal Sussex Regiment) Light Anti-Aircraft Regiment, Royal Artillery
American Civil War regiments 109th Illinois Infantry Regiment 109th New York Infantry Regiment 109th Pennsylvania Infantry Regiment
See also 109th Brigade (disambiguation) 109th Division (disambiguation)