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

Breitenau belongs to the Verbandsgemeinde of Ransbach-Baumbach, a kind of collective municipality.

The municipal council is made up of 12 council members, including the honorary and presiding mayor (Ortsbürgermeister), who were elected in a majority vote in a municipal election on 7 June 2009.

The yearly high point is the "Singende, klingende Haiderbach" with the Haiderbach Choir Association and the church choir, which always takes place on the first Saturday in April.

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