Diabolo was a German automobile manufacturer, operating as Diabolo Kleinauto GmbH in Stuttgart. The company produced a three-wheeled vehicle in the style of a Morgan, powered by a 1.1-litre V-twin Motosacoche engine.
Compared to many of its contemporaries, the Diabolo three-wheeler was technically more refined, which contributed to its relatively long production life. Despite this, the marque eventually could not withstand competition from four-wheeled cars and ceased production.
Among its notable owners, a Diabolo was the first car of the German film star Heinz Rühmann.