The GNU Project was launched in January 1984 by Richard Stallman, to develop a complete UNIX-style operating system which is comprised of free software: the GNU system. Variants of the GNU operating system, which use the Linux kernel, are now widely used.

The GNU project is closely linked to the philosophy of free software, which is central to the projects that derive from it, such as Ubuntu. The concept of free software is explained at the section called “Free Software”.