Wildenstein Castle () is a ruined hill castle on a hill, , in the Wildenstein valley (Wildensteiner Tal), hidden in a wood at the foot of the Donnersberg near Dannenfels in the county of Donnersbergkreis in the German state of Rhineland-Palatinate.
The castles is of the motte and bailey type. Together with the three other ruined castles of Falkenstein, Hohenfels and Tannenfels, it forms the ring of the "Donnersberg Castles".