| Googlebook OS | Google DeepMind, Google | — | — |
| Haiku | Michael Phipps, Haiku Inc. | 2002 | MIT License |
| Halium | — | — | — |
| HarmonyOS | Huawei | 2019 | — |
| HPE Cray Operating System | — | — | — |
| Hyperbola GNU/Linux-libre | — | — | — |
| Illumos | — | — | Common Development and Distribution License version 1.0 |
| Inspur K-UX | Inspur | — | — |
| Kali Linux | OffSec | 2013 | GNU General Public License |
| Kali Purple | OffSec | — | GNU General Public License |
| KDE neon | KDE | 2016 | GNU General Public License |
| KeshOS | — | — | — |
| Kubuntu | Canonical Ltd. | 2005 | GNU General Public License |
| LibreELEC | — | — | GNU General Public License, version 2.0 |
| Lilith | — | — | MIT License |
| Linux Kodachi | — | — | Apache Software License 2.0 |
| Linux Mint | — | 2006 | GNU General Public License |
| Linux Unified Kernel | — | — | GNU General Public License, version 2.0 |
| Lubuntu | Canonical Ltd. | — | GNU General Public License |
| Lunar Linux | — | — | GNU General Public License |
| LuxOS | — | — | GNU General Public License v3.0 or later |
| Mac OS X Leopard | Apple Inc. | 2007 | Apple Public Source License, end-user license agreement |
| Mac OS X Lion | Apple Inc. | 2011 | Apple Public Source License |
| Mac OS X Snow Leopard | Apple Inc. | 2009 | Apple Public Source License |
| Mac OS X Tiger | Apple Inc. | 2005 | — |
| MacOS | Apple Inc. | 2001 | BSD licenses, proprietary license, Apple Public Source License |
| MacOS Big Sur | Apple Inc. | 2020 | proprietary license, Apple Public Source License |
| MacOS Catalina | Apple Inc. | 2019 | Apple Public Source License |
| MacOS High Sierra | Apple Inc. | 2017 | Apple Public Source License |
| MacOS Mojave | Apple Inc. | 2018 | Apple Public Source License |
| MacOS Monterey | Apple Inc. | 2021 | proprietary license, Apple Public Source License |
| MacOS Sequoia | Apple Inc. | — | — |
| MacOS Sierra | Apple Inc. | 2016 | Apple Public Source License |
| MacOS Tahoe | — | — | — |
| MacOS Ventura | Apple Inc. | 2022 | — |
| Maemo Leste | — | — | — |
| Mageia | — | — | GNU General Public License |
| MakuluLinux | — | — | — |
| Mandriva Linux | Mandriva | — | GNU General Public License |
| Manjaro | Philip Müller | 2011 | free software |
| MenuetOS | — | — | proprietary license, GNU General Public License, version 2.0 |
| MEPIS | Warren Woodford | — | GNU General Public License |
| Midori | Microsoft | — | — |
| MX Linux | — | — | GNU General Public License |
| Netrunner | Blue Systems | — | GNU General Public License |
| NetSecL OS | — | — | GNU General Public License |
| NixOS | Thomas Tuegel, Eelco Dolstra | — | MIT License |
| Nobara (operating system) | Thomas Crider | — | — |