The O-Bahn Busway is a guided busway that is part of the bus rapid transit system servicing the northeastern suburbs of Adelaide, South Australia. The O-Bahn system was conceived by Daimler-Benz to enable buses to avoid traffic congestion by sharing tram tunnels in the German city of Essen.

Guided buses are buses capable of being steered by external means, usually on a dedicated track or roll way that excludes other traffic, permitting the maintenance of schedules even during rush hours. Unlike railbus, trolleybuses or rubber-tyred trams, for part of their routes guided buses are able to share road space with general traffic along conventional roads, or with conventional buses on standard bus lanes.