Bundesautobahn 63 (translates from German as Federal Motorway 63, short form Autobahn 63, abbreviated as BAB 63 or A 63) is an autobahn in southwestern Germany.

It connects the Mainz area to Kaiserslautern and the A 6 and is therefore an important connection between the Rhine/Main and the Saar areas.

It was constructed during the 1980/90s and finished in 2004 (21 years ago) (2004): last section Sembach to Kaiserslautern.

Historically an uninterrupted Autobahn, one final 10-kilometre (6.2 mi) section was added between Sembach and Kaiserslautern at the current site of the Dreieck Kaiserslautern/KL-Zentrum Ausfahrt.

This relieved the heavy traffic on the two lane Bundesstraße 40.