B6) is a German federal highway running from Bremerhaven on the North Sea coast in a southeasterly direction through the states of Lower Saxony, Bremen, Saxony-Anhalt and Saxony to Görlitz on the Polish border.

Before World War II and the implementation of the Oder–Neisse line, the R6 road continued southeastwards from Görlitz via Hirschberg (present-day Jelenia Góra, Poland) and Schweidnitz (Świdnica) to the Silesian capital Breslau (Wrocław) and from there via Oels (Oleśnica) as far as the former Polish border near Groß Wartenberg (Syców).

As a result of the opening of the A 27 motorway between Cuxhaven and Bremen-Nord (formerly Bremen-Burglesum) in the mid- to late-1970s the B6 was replaced by the A 27.

The old route in Cuxhaven from the start (Poststraße/Deichstraße crossroads), apart from the Rohdestraße as far as the branch to the motorway slip road at Altenwalde junction was renamed the B73.

The rest of the route to Bremen, with the exception of a short section in Bremerhaven, was downgraded to Landesstraße 135.