Relsberg is an Ortsgemeinde – a municipality belonging to a Verbandsgemeinde, a kind of collective municipality – in the Kusel district in Rhineland-Palatinate, Germany. It belongs to the Verbandsgemeinde Lauterecken-Wolfstein.
Relsberg lies in the North Palatine Uplands on a ridge between the Lauter and Odenbach valleys at an elevation of some 360 m above sea level in the headwaters of some small streams that run to the Odenbach. The elevations in the immediate vicinity reach beyond 400 m above sea level. Not quite reaching this height on the ordinance survey map are the Bauschüttberg (399 m) and the Kahlenberg (396 m). The municipal area measures 381 ha, of which roughly 10 ha is settled and 46 ha is wooded.
Relsberg borders in the north on the municipality of Reipoltskirchen, in the northeast on the municipality of Hefersweiler, in the south on the municipality of Niederkirchen, in the southwest on the town of Wolfstein and in the west on the municipality of Einöllen.