Schloss Kaltenstein, Medieval château in Vaihingen an der Enz, Germany.

Schloss Kaltenstein is a medieval castle in Vaihingen an der Enz, Baden-Württemberg, built on a limestone rock that rises above the town. Thick walls connect the structure directly to the town below, giving the complex a tight physical relationship with the urban fabric at its foot.

The castle was first recorded in 1096 under the name Castrum Vehingen and served as the seat of the Counts of Vaihingen before passing to new rulers in the 12th century. Later owners reshaped the building several times over the following centuries, adding new sections while keeping parts of the older structure.

The name Kaltenstein, first applied to the rebuilt castle in the 16th century, replaced the earlier name Castrum Vehingen. The CJD youth welfare organisation rented the castle from 1949 until the end of 2013, when it gave up the premises while keeping other facilities nearby. Since 2020 the private Schloss-Collection GmbH & Co KG holds a 27-year building concession to renovate and commercially use the castle.

The castle stands above the old town of Vaihingen an der Enz and can be reached on foot; the climb calls for sturdy shoes. Since the CJD gave up its rented rooms at the end of 2013, the building is no longer a youth hostel. In 2020 the state of Baden-Württemberg granted a 27-year building concession to Wolfgang Scheidtweiler's Private Schloss-Collection GmbH & Co KG, which must first renovate the castle, so access may be restricted during works.

Part of the original medieval shield wall was built into the later structure and remains visible today, standing alongside newer additions without being hidden. This layering of different building phases in one place makes the construction history easy to read just by looking at the walls.