7-Zip is a free and open-source file archiver, a utility used to place groups of files within compressed containers known as "archives". It is developed by Igor Pavlov and was first released in 1999.[2] 7-Zip has its own archive format called 7z, but can read and write several others.

The program can be used from a Windows graphical user interface that also features shell integration, from a Windows command-line interface as the command 7za or 7za.exe, and from POSIX systems as p7zip.[12] Most of the 7-Zip source code is under the LGPL-2.1-or-later license; the unRAR code, however, is under the LGPL-2.1-or-later license with an "unRAR restriction", which states that developers are not permitted to use the code to reverse-engineer the RAR compression algorithm.[13][14]

Since version 21.01 alpha, preliminary Linux support has been added to the upstream instead of the p7zip project.[7]