| Publik | — | — |
| Puppy Linux | — | 2003 |
| Q4OS | — | 2013 |
| QiLinux | — | — |
| Qimo 4 Kids | — | — |
| QP | — | — |
| Qt Extended | Qt Group Plc | — |
| Quantian | Dirk Eddelbuettel | — |
| Raspberry Pi OS | Raspberry Pi Holdings | 2012 |
| ReactOS | Amine Khaldi, Timo Kreuzer, Eric Kohl, Hermès Bélusca-Maïto, Cameron Gutman | — |
| Red Hat Linux | Red Hat | 1994 |
| RedSleeve | — | — |
| RetroPie | — | — |
| ROCK Linux | — | — |
| RTEMS | Sebastian Huber, Joel Sherrill | — |
| Sabayon Linux | — | — |
| Sabily | — | — |
| Sacix | — | — |
| SambaEdu | — | — |
| SchilliX | — | — |
| Scientific Linux | Fermilab | — |
| SHR | — | — |
| Siduction | — | 2011 |
| Slackware | Patrick Volkerding | — |
| Slax | — | — |
| SliTaz | — | — |
| SME Server | — | — |
| Soft Hard Real-Time Kernel | Sant'Anna School of Advanced Studies | — |
| Softlanding Linux System | Peter MacDonald | 1992 |
| Solus | — | — |
| SONiC | Microsoft, Open Compute Project | 2016 |
| SparkyLinux | — | — |
| SPBLinux | — | — |
| Subgraph OS | — | — |
| SuSE Linux | SUSE, Novell | — |
| SUSE Linux Enterprise Server | SUSE | — |
| Syllable Desktop | — | — |
| Symphony OS | — | — |
| SystemRescue | — | — |
| T2 SDE | René Rebe | — |
| Thinstation | — | — |
| Tiny Core Linux | — | — |
| Tomato | — | — |
| TopologiLinux | — | — |
| Trinity Rescue Kit | — | 2010 |
| Trustix | Comodo Group | — |
| Tuga | — | — |
| TWRP | — | — |