Line B is a line on the Lyon Metro in France that runs between Charpennes–Charles Hernu and Saint-Genis-Laval–Hôpital Lyon Sud. It was constructed using the cut-and-cover method, and went into service on 2 May 1978. Together with Line A, it was one of the inaugural lines of the Lyon Metro. It has since been extended three times: from Part-Dieu to Jean Macé in 1981, from Jean Macé to Stade de Gerland in 2000, from Stade de Gerland to Oullins railway station in 2013 and to Saint-Genis-Laval–Hôpital Lyon Sud in 2023. The line serves 12 stations, and is 10.2 kilometres (6.3 mi) long. Line B trains run on tires rather than steel wheels; it is a rubber-tired metro line.

The Lyon Metro is a rapid transit system serving Lyon Metropolis, France. First opened in 1974, it currently consists of four lines, serving 42 stations and comprising 34.4 kilometres (21.4 mi) of route. Part of the Transports en Commun Lyonnais (TCL) system of public transport, it is supported by two funiculars and a tramway network.