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:

• the Rhein-Ruhr-Marathon
• the Verkehrsverbund Rhein-Ruhr
• the Rhein-Ruhr S-Bahn
• the RheinRuhrZentrum - RRZ
• RR Rhine Ruhr (PTY) Ltd, an Australian engineering firm
• RRI Rhein Ruhr International GmbH, a German engineering firm

• Oak Lantern
• Oaklawn and St. Louis Cemeteries Historic District
• Oak Lawn Comm. HS 229
• Oak Lawn Community HS
• Oak Lawn (Metra station)
• Oaklawn Park Race Track
• Oak Lawn station (Illinois)
• Oak Lawn station (Metra)
• Oak Lea
• Oak leaf butterflies
• Oakleaf cyanea
• Oak-leaf dryandra
• Oak-leafed dryandra
• Oakleaf fern
• Oakleaf geranium
• Oakleaf mountain ash
• Oak leaf pattern
• Oak leaf rolling weevil
• Oak leafrolling weevil
• Oak leaf skeletonizer
• Oak-leaf thomasia
• Oak leaf tier
• Oak leaftier
• Oak leaftier Moth
• Oak leaftier moth