The Rhine-Ruhr metropolitan region (German: Metropolregion Rhein-Ruhr) is the largest metropolitan region in Germany with over 11 million inhabitants. It is of polycentric nature and the only megacity in Germany. It covers an area of 7,110 square kilometers and lies entirely within the federal state of North Rhine-Westphalia. The Rhine-Ruhr metropolitan region spreads from Dortmund-Bochum-Essen-Duisburg (Ruhr Area) in the north, to the urban areas of the cities of Mönchengladbach, Düsseldorf (the state capital), Wuppertal, Leverkusen, Cologne (the region's largest and Germany's fourth largest city), and Bonn in the south. The location of the Rhine-Ruhr at the heart of the European blue banana makes it well connected to other major European cities and metropolitan areas like the Randstad, the Flemish Diamond and the Frankfurt Rhine Main Region.

The metropolitan area is named after the Rhine and Ruhr rivers, which are the regions's defining geographical features and historically its economic backbone.

Rhine-Ruhr (German: Metropolregion Rhein-Ruhr, also called Rhein-Ruhr-Region or Rhein-Ruhr-Gebiet) usually refers to the Rhine-Ruhr Metropolitan Region in Western Germany. It may also refer to: