15th Regiment or 15th Infantry Regiment may refer to:
15th Field Artillery Regiment (Canada)
15th Infantry Regiment (South Korea) 15th Regiment of Foot, United Kingdom 15th Infantry Regiment (United States) 15th Infantry Regiment (USAFIP-NL), part of United States Army Forces in the Philippines – Northern Luzon 15th New York National Guard Regiment, United States 15th Poznań Uhlan Regiment, Poland 15th Guards Motor Rifle Regiment, Russia
American Revolutionary War regiments 15th Continental Regiment 15th Massachusetts Regiment 15th Virginia Regiment
American Civil War regiments
Confederate (Southern) Army regiments 15th South Carolina Infantry Regiment 15th Alabama Infantry Regiment
Union (Northern) Army regiments 15th Connecticut Infantry Regiment 15th Illinois Infantry Regiment 15th Illinois Cavalry Regiment 15th Iowa Infantry Regiment 15th Massachusetts Infantry Regiment 15th West Virginia Infantry Regiment 15th Wisconsin Infantry Regiment
See also XV Corps (disambiguation) 15th Army (disambiguation) 15th Division (disambiguation) 15th Group (disambiguation) 15th Wing (disambiguation) 15th Brigade (disambiguation) 15 Squadron (disambiguation)