The Teufelsburg is a castle ruin in Felsberg in the community of Überherrn, Saarland, Germany.

The Teufelsburg castle ruin lies to the west of Saarlouis on the edge of the middle Saartal at a height of 320 m above Sea level.

The first documented reference to the castle as "Neufilsberg" (= Neu-Felsberg) dates to 1370, and the first knight of Neufelsberg Castle was Arnold von Filsberg - a grandson of Arnold von der Brücke, Lord of Siersburg and Felsberg.

The final historical reference to the castle occurs in 1699 when it was already in ruins and no longer inhabited.

Since April 2007, the museum displays tools and utensils from the castle mountain's sandstone quarry as well as fossils and minerals from the Felsberg.