BSA is a binary archive format used by computer games developed by Bethesda Softworks. BSA files store various game assets, such as textures, settings, audio tracks, or 3D models and objects.

One of the most famous games that uses BSA files is Fallout. BSA files are very often modified by Bethesda games fans and community members to change some game elements or add new ones that enhance the gameplay, for example, new textures or objects. BSA files are supported by some third-party tools.