| Slamd64 | — | — | — |
| Slax | — | — | GNU General Public License |
| SlimPup | — | — | — |
| SlimRom | — | — | — |
| Slis | — | — | — |
| SME Server | — | — | GNU General Public License |
| SmoothWall | — | — | GNU General Public License, version 2.0 |
| Snøfrix | — | — | — |
| Softlanding Linux System | Peter MacDonald | 1992 | GNU General Public License |
| Solus | — | — | GNU General Public License |
| SolydXK | — | 2013 | — |
| Sorcerer | — | — | — |
| Source Mage | — | — | — |
| SparkyLinux | — | — | GNU General Public License |
| SPBLinux | — | — | GNU General Public License |
| SpiralLinux | — | — | — |
| Splashtop | — | — | proprietary license |
| Splashtop OS | Splashtop Inc. | — | — |
| Stali | Anselm R. Garbe | — | — |
| SteamOS | Valve Corporation | — | — |
| Suicide Linux | — | 2009 | proprietary license |
| Sunwah Linux | — | — | — |
| SuperX | — | — | — |
| SuSE Linux | SUSE, Novell | — | GNU General Public License |
| SUSE Linux Enterprise Desktop | SUSE | — | GNU Lesser General Public License |
| SUSE Linux Enterprise Server | SUSE | — | GNU General Public License |
| Symphony OS | — | — | GNU General Public License |
| SystemRescue | — | — | GNU General Public License |
| T2 SDE | René Rebe | — | GNU General Public License |
| Tails | The Tor Project, Inc | 2009 | GNU General Public License v3.0 or later |
| Tanglu | — | — | — |
| TeaLinuxOS | — | — | — |
| TeaM-TL | — | 2004 | — |
| The Linux Schools Project | — | — | — |
| Tilix | — | — | — |
| Tinfoil Hat Linux | — | — | BSD licenses |
| Tiny Core Linux | — | — | GNU General Public License |
| TinyMe | — | — | — |
| Tisa Linux | — | — | — |
| Tomato | — | — | GNU General Public License |
| Tomsrtbt | — | — | — |
| TopologiLinux | — | — | GNU General Public License |
| Toutankinux | — | — | — |
| Toutou Linux | — | — | — |
| Tri-Lab Operating System | — | — | — |
| Trinity Rescue Kit | — | 2010 | GNU General Public License |
| Trinux | — | — | GNU General Public License, version 2.0 |
| Trisquel | — | 2007 | GNU General Public License, version 3.0 |