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 3 km (1.9 mi) it flows into a pond.

From the bifurcation of left flowing Silberbach, it divides again after a few kilometers, and some of the water flows back to the Kaltenmühlbach. The Silberbach flows directly into the Waldnaab.

After the Kaltenmühlbach has regenerated after its turn, it flows through a deep valley, where it grows by numerous creeks into a small river. After a few farms, it flows under the road 2172 (Plößberg - Bärnau), and then helps the fledgling Waldnaab flow.

• Urtlbach

• List of rivers of Bavaria