Kaltenmühlbach is a 6.8-kilometre-long (4.2 mi) left tributary of the Waldnaab in the Upper Palatinate in Bavaria, Germany.

It rises in the High Thaner Forest and flows to the Waldnaab.

The Kaltenmühlbach springs at 815 m (2,674 ft) above sea level from the so-called Three Wells (Drei Brunnen) at the foot of Entenbühl (901 m (2,956 ft)) near the border of the Silberhütte.

After only a few hundred meters, it becomes a little stream in the hamlet Altglashütte.

After the Kaltenmühlbach has regenerated after its turn, it flows through a deep valley, where it grows by numerous creeks into a small river.