Deutsche Bahn AG (DB AG, DBAG or DB) is the German national railway company, a private joint-stock company (AG) with its headquarters in Berlin. It came into existence in 1994 as the successor to the former state railways of Germany, the Deutsche Bundesbahn of West Germany and the Deutsche Reichsbahn of East Germany. It also gained ownership of former railway assets in West Berlin held by the VdeR. Its name means "German Railway" in German.

DB is organized as a business group and has over 1000 subsidiaries, of which 287 are in Germany. It describes itself as the second-largest transport company in the world, after Deutsche Post AG, and is the largest railway operator and infrastructure owner in Europe. It carries about two billion passengers each year.

DBAG has taken over the abbreviation and logo DB from the West German state railway Deutsche Bundesbahn, although it has modernised the logo. Erik Spiekermann designed the new corporate font DB type.

Originally, DBAG had its headquarters in Frankfurt am Main but moved to Potsdamer Platz in central Berlin in 1996, where it occupies a 26-story office tower designed by Helmut Jahn at the eastern end of the Sony Center and named BahnTower. As the lease was to expire in 2010, DB had announced plans to relocate to Berlin Hauptbahnhof, and in 2007 a proposal for a new headquarters by 3XN Architects won an architectural competition which also included Foster + Partners, Dominique Perrault and Auer + Weber. However, these plans have been put on hold, and the BahnTower leased for at least three more years.