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

The community belongs to the Verbandsgemeinde of Wallmerod, a kind of collective municipality.

Right through the community runs Bundesstraße 255, linking Montabaur and Rennerod.

The nearest InterCityExpress stop is the railway station at Montabaur on the Cologne-Frankfurt high-speed rail line.

Westfalia Separator makes decanters at its Niederahr works.