| Jurix | — | — | GNU General Public License |
| JUX | — | — | — |
| Kaella | — | — | — |
| KahelOS | — | — | — |
| KaiOS | KaiOS Technologies, Inc. | — | GNU General Public License, version 2.0 |
| Kaisen Linux | — | — | — |
| Kalango Linux | — | — | — |
| Kali Linux | OffSec | 2013 | GNU General Public License |
| Kali Purple | OffSec | — | GNU General Public License |
| Kanotix | — | — | — |
| KaOS | — | 2013 | GNU General Public License |
| KDE Linux | KDE | — | — |
| KDE neon | KDE | 2016 | GNU General Public License |
| KISS Linux | — | — | — |
| Kiwi Linux | — | — | — |
| Knopperdisk | — | — | — |
| Knoppix | Klaus Knopper | — | GNU General Public License |
| Knoppix STD | — | — | — |
| KnoppMyth | — | — | — |
| Kongoni GNU/Linux | — | — | — |
| Korora | — | 2016 | GNU General Public License |
| KSI Linux | — | — | — |
| Kubuntu | Canonical Ltd. | 2005 | GNU General Public License |
| Kurumin | Carlos Morimoto | — | GNU General Public License |
| Kwort Linux | — | — | — |
| Lakka | — | — | — |
| LEDE | — | — | GNU General Public License |
| Leeenux | — | — | — |
| Lernstick | — | — | — |
| Libranet | — | — | — |
| LibreCMC | — | — | GNU General Public License, version 2.0 |
| LibreELEC | — | — | GNU General Public License, version 2.0 |
| Lightweight Portable Security | United States Department of Defense | 2011 | — |
| Lihuen GNU/Linux | — | — | — |
| LiMux | — | — | — |
| Linkat | Generalitat of Catalonia | — | GNU General Public License |
| Linpus Linux | — | — | GNU General Public License |
| Linux Galiza | — | — | — |
| Linux Kamarada | — | — | — |
| Linux Kodachi | — | — | Apache Software License 2.0 |
| Linux Mint | — | 2006 | GNU General Public License |
| Linux Mint Debian Edition | — | — | GNU General Public License |
| Linux XP | — | — | GNU General Public License |
| LinuX-gamers | — | — | — |
| Linux-Musterlösung | — | — | GNU General Public License |
| Linux4Space | — | — | — |
| Linuxacessivel.org | — | — | GNU General Public License |
| Linuxcare Bootable Toolbox | Linuxcare | — | — |