In what year was the Linux kernel first released? It was first released in 1991.
Linux's earliest public release was version 0.01, uploaded by Linus Torvalds on September 17, 1991. It was not yet a polished or independently bootable operating system: its code still depended on MINIX for compilation and testing. Torvalds then announced version 0.02 on October 5, 1991, generally treated as the first official Linux release.
The year 1991 can therefore refer to both the first source release and the first official announcement. Version 0.11, released in December 1991, was a major early milestone because it was the first version capable of being self-hosted—that is, compiled on a system running the Linux kernel itself.
Readers sometimes confuse the kernel's release date with Linux distribution dates. Distributions such as MCC Interim Linux appeared in 1992 and combined the kernel with installation tools and other software. Linux 1.0 arrived much later, on March 14, 1994. The kernel also became the core of the GNU/Linux operating system, alongside GNU utilities.