TAR is a data archive file created with Unix-based archiving tool tar. TAR files cane store multiple files in an uncompressed archive format. The format was originally designed for archiving data on magnetic tapes, but is still used today for archiving digital data on any storage devices.

TAR archives may be compressed with external tools, which can use gzip, lzma, bzip2, or compress methods. A compressed archive is given an additional suffix that informs which compression method was used, for example, a gzip archive is given an additional GZ suffix.