| Q4OS | — | 2013 | GNU General Public License |
| Qasedak distro | — | — | — |
| QiLinux | — | — | GNU General Public License |
| Qimo | — | — | — |
| Qimo 4 Kids | — | — | GNU General Public License |
| QNodeOS | QuTech | — | — |
| QNX | BlackBerry, QNX Software Systems | — | — |
| QP | — | — | GNU General Public License |
| Qt Extended | Qt Group Plc | — | GNU General Public License |
| QtMoko | — | — | — |
| Quantian | Dirk Eddelbuettel | — | GNU General Public License |
| Qubes OS | — | — | GNU General Public License, version 2.0 |