GBX is an extension characteristic of the files most often used by the Nadeo series of games called TrackMania. GBX files are used to store various game data, but most often include maps, driving routes, graphics, and replay videos. Installation of GBX files is as simple as placing the GBX file in the directory where the game is located.

GBX are files also used by other games published by Nadeo. The company has been owned by Ubisoft Entertainment SA since 2009.