The Salzburg trolleybus system forms part of the public transport network serving Salzburg, capital of the federal state of Salzburg in Austria. Opened on 1 October 1940, it replaced the Salzburg tramway network.
One of only two such systems currently operating in Austria, the Salzburg trolleybus system is one of the largest trolleybus systems in western Europe. It presently carries 38 million passengers each year.
Together with the Salzburger Lokalbahn, the system is currently operated by Salzburg AG, which markets it under the name StadtBus Salzburg. It is also integrated into the Salzburger Verkehrsverbund. Along with the Salzburg S-Bahn, it forms the backbone of the Salzburg's public transport network; the city's diesel bus network, operated by Albus Salzburg, plays only a minor role.
On 1 October 1940, the first trolleybus ran through the streets of Salzburg, on the Siegmundsplatz–Maxglan route, which is now part of line 1. A few days later, on 24 October 1940, the extension to Makartplatz followed, and on 10 November 1940, the line was further extended, to Salzburg Hauptbahnhof. On 16 February 1942, the ring lines M and L (Maxglan–Lehen–Hauptbahnhof–Zentrum–Maxglan) came into operation. In the following years, the Salzburg trolleybus system recorded rapid growth, but the tramway network was destroyed.