The river Horn (French: Horn, pronounced [ɔʁn]；German: Hornbach, pronounced [ˈhɔʁnˌbax] ) is a left tributary of Schwarzbach flowing through the department of Moselle, in northeastern France, and the state of Rhineland-Palatinate, in southwestern Germany.

The Horn's headwaters rise in the French town of Bitche, in the Moselle Department, following a north by north-eastern course, before forming a part of the border between France and Germany. As the Franco-German border takes a sharp turn to the west, the Horn continues into Germany. Here, it follows a roughly north-western course, ending in the German town of Zweibrücken, emptying into the Schwarzbach. Its length in France is 27.6 km (17.1 mi).

• List of rivers of Rhineland-Palatinate