Altena Castle (German: Burg Altena) is a medieval hill castle in the town of Altena in North Rhine-Westphalia. Built on a spur of Klusenberg hill, the castle lies near the Lenne in the Märkischer Kreis.

The castle was erected by the early Counts of Berg in the early 12th century. Eventually, the House of Berg abandoned Altena and moved their residence to Hamm.