Old Wolfstein Castle (German: Burg Alt-Wolfstein, also called the Altes Schloß),[1] is a ruined hillside castle on the eastern slopes of the Königsberg at the narrowest point in the Lauter valley near Wolfstein in the county of Kusel in the German state of Rhineland-Palatinate.

Baldwin of Luxembourg made several unsuccessful attempts to acquire the castle through an imperial mortgage (Reichspfandschaft).

In the 19th and 20th centuries the ruins came into the possession of the Kingdom of Bavaria and, since 1963, have been managed by the Castle Authorities of Rhineland-Palatinate (Schlösserverwaltung von Rheinland-Pfalz).

To the north of the ruins on a steep hillside is rubble from an old wall, which is evidence of the formerly, lower lying outer ward of the castle.

A close observation of the interior wall of the ruined bergfried reveals at a certain height the handle and rear part of a trowel.