The Dernbach is a river in the district of Südliche Weinstraße in the German state of Rhineland-Palatinate.

Its source is located on the eastern slopes of the Langentalkopf, the summit of which is 526 m above sea level.

From its origin, the Dernbach flows in a mainly southerly direction and picks up the waters of several other small streams as well as the Waltersbach, which is just several hundred metres long and joins it from the north, before reaching the village of Ramberg.

Next, the Dernbach flows through its eponymous village where, at the northern edge of the settlement, it is joined by the Leinbach coming from the east.

Below the Vogelstockerhof farm, in the parish of Annweiler am Trifels, the Dernbach merges with the Eußerbach, which arrives from the right coming from the northwest, to form the Eisbach, a feeder of the Rhine tributary, the Queich.