Samuel Perkins Spear (1815 – May 4, 1875) was an American soldier who saw combat in the Seminole Wars, the Mexican–American War, and the Civil War. Spear enlisted in the army in 1833, and was assigned twice to the 2nd Dragoons and once to the 2nd Cavalry in which he was promoted from private to first sergeant each time. Spear was discharged from the U.S. Regular Army on August 6, 1861. He was appointed lieutenant colonel of the 11th Pennsylvania Cavalry Regiment and was promoted to colonel on August 20, 1862. He commanded his regiment at the Joint Expedition Against Franklin, October 3, 1862.