Bad Marienberg (Westerwald) is a town in the Westerwaldkreis in Rhineland-Palatinate, Germany, and also the seat of the like-named Verbandsgemeinde, a kind of collective municipality.

In the 18th century, the formerly separate communities of Obermarienberg, still an easily recognizable ring-shaped settlement around the parish church today, and Untermarienberg grew together.

After they died out, Count Johann VI of Nassau-Dillenburg ("the Elder") received the inheritance, thereby uniting these German lands – albeit only for a short time.

After further territorial exchanges within the Nassau dynasty through inheritances, Marienberg ended up, as part of the Beilstein lordly domain, under Prince William IV's governance.

Along with the lordly domain of Beilstein, the village fell in 1806 to the Napoleonic Grand Duchy of Berg, in which, in 1808, it was grouped into the Arrondissement of Dillenburg within the Département of Sieg.

In the course of a short-lived administrative reform, Marienberg was annexed in 1849 to the newly founded Landkreis (rural district) of Hachenburg, before the old arrangement was brought back into force in 1854.

Having had town rights conferred on 1 April 1939, Marienberg then belonged to the French occupation zone and was part of the Upper Presidium of Rhineland-Hesse-Nassau.

[5] The town maintains partnership arrangements with the district seat of Marienberg in the Ore Mountains (Erzgebirge) and with Pagny-sur-Moselle in France.

Within Bad Marienberg's town limits is a spa garden with a Kneipp centre and a bandshell where concerts are regularly held in the summer.

Bad Marienberg is home to these worldwide operating companies: KEMPF Fahrzeugbau[6] LEBEK International Fashion Group[7] MENK Apparatebau[8] Right near the town runs Bundesstraße 414 leading from Driedorf-Hohenroth to Altenkirchen.

The nearest InterCityExpress stop is the railway station at Montabaur on the Cologne-Frankfurt high-speed rail line, which is approximately 30 km away.