A TAR file is an archive created by tar, a Unix-based utility used to package files together for backup or distribution purposes. It contains multiple files stored in an uncompressed format along with metadata about the archive. TAR files are commonly compressed into .GZ files with GNU Zip compression.

The TAR format was introduced with the tar utility in 1979 to write data to tape drives, which were data storage devices that would read and write data on magnetic tape. The TAR name comes from "Tape archive." In modern computing, the TAR format is typically used on Unix and Linux systems to consolidate multiple files into one file. The tarballs are especially helpful for backing up files or transporting multiple files to another location. Users may also compress TAR files to reduce their size. TAR archives compressed with GNU Zip compression may become GZ, .TAR.GZ, or .TGZ files. Compressed archives with .tar.gz and .tgz file extensions are often used for packaging software installers. NOTE: TAR files are often referred to as "tarballs," since they collect all types of files into one file, similar to a sticky tarball.