William Allen (1845 – January 8, 1882) was a U.S. Army soldier who fought during the Indian Wars in the post-American Civil War period. Serving under Lieutenant Colonel George Crook, he participated in expeditions against the Apache in the Arizona Territory throughout the 1870s. He was one of four men who received the Medal of Honor for the Battle of Turret Peak against the Yavapai Apaches in 1873.