The Bonn Stadtbahn is a Stadtbahn system in Bonn and the surrounding Rhein-Sieg area, that also includes the Bonn Straßenbahn. Although with six actual Stadtbahn lines the network is relatively small, two of Bonn's Stadtbahn lines connect to the much larger Cologne Stadtbahn.

Stadtbahn is a German word referring to various types of urban rail transport. One type of transport originated in the 19th century, firstly in Berlin and followed by Vienna, where rail routes were created that could be used independently from other traffic.