Montabaur was one of the five Regierungsbezirke of Rhineland-Palatinate, Germany into which the newly founded state was divided until 1968.

Regierungsbezirk Wiesbaden, formed in 1866 as part of the Prussian province of Hesse-Nassau, had been divided by after the Second World War by the occupying powers as it lay astride a zone boundary.

The majority of the Regierungsbezirk lay in the American Zone and became part of the state of Hesse in 1945.

The Regierungsbezirk of Montabaur was dissolved on 1 October 1968 and incorporated into Koblenz.

[1] The area of Regierungsbezirk Montabaur largely corresponds to the modern counties of Rhein-Lahn-Kreis and Westerwaldkreis.