Morgan Seth Earp (April 24, 1851 – March 18, 1882) was an American sheriff and lawman. He served as Tombstone, Arizona's Special Policeman when he helped his brothers Virgil and Wyatt, as well as Doc Holliday, confront the outlaw Cochise County Cowboys in the Gunfight at the O.K. Corral on October 26, 1881.