| U-Lite | — | — |
| UberStudent | — | — |
| Ubuntu Budgie | — | — |
| Ubuntu for Android | Canonical Ltd. | — |
| Ubuntu GNOME | Canonical Ltd. | 2016 |
| Ubuntu Kylin | National University of Defense Technology | — |
| Ubuntu MATE | — | — |
| Ubuntu Mobile | Canonical Ltd. | — |
| Ubuntu Netbook Edition | Canonical Ltd. | — |
| Ubuntu Server Edition | Canonical Ltd. | 2006 |
| Ubuntu Studio | Canonical Ltd., Ubuntu Foundation | 2007 |
| Ubuntu Touch | UBports | 2013 |
| Ufficio Zero | — | 2020 |
| Ultima Linux | — | — |
| USU | — | — |
| Ututo | — | — |
| Volumio (music player) | — | — |
| VSTa | — | — |
| Vyatta | Brocade Communications Systems | — |
| WebOS | LG Electronics | — |
| White Box Enterprise Linux | — | — |
| Whonix | — | 2012 |
| Wombat OS | — | — |
| Xandros | — | — |
| Xinux | UZINFOCOM | — |
| Yellow Dog Linux | Fixstars Solutions | — |
| Zentyal | — | — |
| Zenwalk | — | — |
| Zeroshell | — | — |
| ZevenOS | — | — |
| Zorin OS | Zorin Technology Group Ltd. | 2009 |
| Ångström distribution | — | — |