| 3CX Phone System | — | — | end-user license agreement |
| 4MLinux | — | — | — |
| 64 Studio | — | — | GNU General Public License |
| ABCbuntu | — | — | — |
| Abitti | The Matriculation Examination Board of Finland | — | — |
| Absolute Linux | — | — | GNU General Public License |
| Adamantix | — | — | GNU General Public License |
| Adélie Linux | — | — | — |
| AerOS | — | — | — |
| AerynOS | — | — | — |
| AgiliaLinux | — | — | — |
| Alinex | — | — | — |
| ALinux | — | — | — |
| AliOS | Alibaba Group | — | — |
| AlmaLinux | Andrew Lukoshko | — | — |
| ALT Linux | ALT Linux Team, ALT Linux | — | GNU General Public License, version 2.0 or later |
| Alter Linux | — | — | — |
| Amber Linux | — | — | — |
| AmogOS | — | — | 4-clause BSD License |
| AmonEcole | EOLE | — | — |
| AnduinOS | — | — | GNU General Public License, version 3.0 |
| Antergos | — | 2013 | GNU General Public License |
| Anthon OS | — | — | — |
| AntiX | — | — | GNU General Public License |
| AOSC OS | Anthon Open Source Community | — | — |
| Apricity OS | Alex Gajewski | — | — |
| Aptosid | — | 2006 | GNU General Public License |
| Arch Linux | Allan McRae, Anatol Pomozov, Aaron Griffin, Felix Yan | 2002 | GNU General Public License |
| Arch Linux 32 | — | — | — |
| Arch Linux ARM | — | — | — |
| ArchBang | — | 2010 | GNU General Public License |
| Archcraft | — | — | — |
| Archie Linux | — | — | — |
| ArchLabs | — | — | — |
| ArcoLinux | — | — | — |
| Ark Linux | — | 2005 | — |
| ArkOS | — | — | MIT License |
| ArkOS | — | — | GNU General Public License |
| ARMA aka Omoikane GNU/Linux | — | — | — |
| Armbian Linux | — | — | GNU General Public License, version 3.0 |
| ArtistX | — | — | — |
| Artix Linux | — | 2017 | — |
| Asahi Linux | Asahi Lina, Alyssa Rosenzweig, Hector Martin | 2021 | — |
| Asianux | — | — | — |
| AskoziaPBX | — | — | — |
| ASLinux Desktop | — | — | — |
| Astra Linux | RusBITech | — | GNU General Public License |
| Asturix | — | — | GNU General Public License |