Bey Ertan of Kastamon (13 December 1342-) was the Ottoman Bey of Kastamon from 30 September 1356, succeeding Bey Kemal of Kastamon. He was the son of Bey Tutus of Kastamon, and he succeeded his older brother on his murder. In 1361, he gave permission for his sister Gulfem to marry Beylerbey Saltuk of Ankara, a son of Suleyman Pasha.