BZ2 is the extension given to files that store compressed data archives created by the Bzip 2 program. This program is most often found in Linux and Unix-based systems. It can only compress individual files. If you want to create a multi-file archive in this format, such files must first be archived.

BZ2 files are sometimes used to distribute software for Linux systems. The compression in these files is based on the Burrows-Wheeler algorithm.