The Vienna S-Bahn is a suburban commuter rail network in Vienna, Austria. As opposed to the city-run urban metro network, the Vienna U-Bahn, it extends beyond the borders of the city, is operated by the ÖBB, and consists of many branch lines. S-Bahn is short for Schnellbahn, which can be translated as "rapid railway".

The Vienna U-Bahn, where U-Bahn is an abbreviation of the German word Untergrundbahn, is a rapid transit system serving Vienna, Austria. The five-line network consists of 83.1 kilometers (51.6 mi) of route, serving 109 stations. It is the backbone of what the International Association of Public Transport (UITP) deemed one of the best-performing public transport systems worldwide in 2009. 459.8 million passengers rode the U-Bahn in 2019. The network is undergoing expansion and rolling stock renewal. Since 1969, 200 million euros have been invested annually in the extension of the Vienna U-Bahn.