| Kali Purple | OffSec | — | GNU General Public License |
| KolibriOS | — | — | GNU General Public License, version 2.0 |
| Kubuntu | Canonical Ltd. | 2005 | GNU General Public License |
| LAN Manager | 3Com, Microsoft | — | proprietary license |
| LiMux | — | — | — |
| LineageOS | — | 2016 | GNU General Public License, version 2.0, Apache License |
| Linux Mint | — | 2006 | GNU General Public License |
| LNX-BBC | — | — | — |
| Lubuntu | Canonical Ltd. | — | GNU General Public License |
| Microsoft Windows | Microsoft | 1985 | proprietary license |
| MilaX | — | — | Common Development and Distribution License |
| MINIX | Andrew S. Tanenbaum | — | 3-clause BSD License |
| Minoca OS | — | — | GNU General Public License, version 3.0 |
| MIUI | Xiaomi | — | GNU General Public License, version 3.0, Apache Software License 2.0 |
| Morphix | — | — | GNU General Public License |
| MuLinux | — | — | GNU General Public License |
| MX Linux | — | — | GNU General Public License |
| NetBSD | — | 1993 | BSD licenses |
| Netrunner | Blue Systems | — | GNU General Public License |
| NeXTSTEP | NeXT | — | proprietary license |
| NOS | Alien Internet Services | — | — |
| Nura | — | — | GNU General Public License, version 3.0 |
| OpenWrt | Gábor Juhos, Florian Fainelli, Hauke Mehrtens, Jo-Philipp Wich | 2004 | GNU General Public License, version 2.0 |
| OS/2 | IBM, Microsoft | — | proprietary license |
| PC-UX | NEC | 1984 | — |
| PCLinuxOS | — | — | — |
| Pinguy OS | — | — | GNU General Public License |
| Plan 9 | Bell Labs | 1992 | GNU General Public License, version 2.0, MIT License, Lucent Public License |
| Porteus | — | — | GNU General Public License |
| PTS-DOS | Paragon Software Group | 1993 | proprietary license |
| Puppy Linux | — | 2003 | GNU General Public License |
| Raspberry Pi OS | Raspberry Pi Holdings | 2012 | GNU General Public License |
| ReactOS | Amine Khaldi, Timo Kreuzer, Eric Kohl, Hermès Bélusca-Maïto, Cameron Gutman | — | GNU Lesser General Public License, GNU General Public License |
| Red Hat Linux | Red Hat | 1994 | GNU General Public License |
| Red Star OS | Korea Computer Center | — | — |
| Rhapsody | Apple Inc. | — | — |
| RIOT | Martin Lenders, Benjamin Valentin, Alexandre Abadie | — | GNU Lesser General Public License, version 2.1 |
| RouterOS | MikroTik | — | — |
| RTEMS | Sebastian Huber, Joel Sherrill | — | GNU General Public License |
| RTX | IntervalZero | — | — |
| Runtu | — | — | — |
| SeaBIOS | — | — | GNU Lesser General Public License, version 3.0 |
| SharpOS | — | — | GNU Lesser General Public License, BSD licenses, GNU General Public License, version 2.0 |
| ShredOS | — | — | GNU General Public License, version 2.0 |
| SimpleLinux | — | — | — |
| Slackware | Patrick Volkerding | — | GNU General Public License |
| Solaris | Sun Microsystems, Oracle Corporation | 1991 | proprietary license |
| SolydXK | — | 2013 | — |