The Sofia trolleybus system (Bulgarian: Тролейбусен транспорт София) forms part of the public transport network of Sofia, the capital city of Bulgaria.

It was over 3 km (2 mi) long, and connected the city with the Gorna Banya quarter.

[2] The line was covered by 2 MAN trolleybuses, which were stored on the last stops during the night, due to the lack of depot.

In the 1950s and 1960s, massive development of the trolleybus transport in Sofia began.

At that time, the construction of new trolleybus routes proceeded especially rapidly, and two depots ("Stochna Gara" and "Nadezhda") were opened, with a total capacity of 160 trolleybuses.