Niederroßbach is an Ortsgemeinde – a community belonging to a Verbandsgemeinde – in the Westerwaldkreis in Rhineland-Palatinate, Germany.

The community lies in the Westerwald between Siegen and Limburg an der Lahn. Through the community flow the Ortsbach and the Roßbach. Niederroßbach belongs to the Verbandsgemeinde of Rennerod, a kind of collective municipality. Its seat is in the like-named town.

Niederroßbach's neighbours are Oberroßbach, Fehl-Ritzhausen, Neustadt and Zehnhausen bei Rennerod.

In 1431, Niederroßbach had its first documentary mention.

The council is made up of 13 council members, including the extraofficial mayor (Bürgermeister).

	FW	FW	Total
2004	7	5	12 seats

Running right near the community are Bundesstraßen 54, linking Limburg an der Lahn with Siegen, and 255, leading from Montabaur to Herborn. The nearest Autobahn interchange is Haiger/Burbach on the A 45 (Dortmund–Hanau), some 17 km away. Between Niederroßbach and Neustadt once lay a halt on the now abandoned Westerwaldquerbahn (railway). The nearest InterCityExpress stop is the railway station at Montabaur on the Cologne-Frankfurt high-speed rail line.

• Niederroßbach in the collective municipality’s Web pages (in German)