Kubuntu is an official flavour of the Ubuntu operating system that uses the KDE Plasma Desktop instead of the GNOME desktop environment. As part of the Ubuntu project, Kubuntu uses the same underlying systems. Every package in Kubuntu shares the same repositories as Ubuntu, and it is released regularly on the same schedule as Ubuntu.

Kubuntu was sponsored by Canonical Ltd. until 2012 and then directly by Blue Systems. Now, employees of Blue Systems contribute upstream, to KDE and Debian, and Kubuntu development is led by community contributors. During the changeover, Kubuntu retained the use of Ubuntu project servers and existing developers.

Name
"Kubuntu" is a registered trademark held by Canonical. It is derived from the name "Ubuntu", prefixing a K to represent the KDE platform that Kubuntu is built upon (following a widespread naming convention of prefixing K to the name of any software released for use on KDE platforms), as well as the KDE community.

Since ubuntu is a Bantu term translating roughly to "humanity", and since Bantu grammar involves prefixes to form noun classes, it turns out that the prefix ku- having the meaning "toward" in Bemba, kubuntu is also a meaningful Bemba word or phrase translating to "toward humanity". Reportedly, the same word, by coincidence, also takes the meaning of "free" in Kirundi.