LinuxTag was an annual Free and Open Source Software (FOSS) conference and exposition with an emphasis on Linux but also BSD descendants located in Germany. The name is a compound with the German Tag meaning "Day", as it was initially a single day conference, but soon extended to multiple days, then always including a weekend. LinuxTag was the world's largest FLOSS conference and exhibition for years and aimed to provide a comprehensive overview of the Linux and Free Software market as well to promote contacts between users and developers. With this broad approach LinuxTag was one of the most important events of this kind.

LinuxTag's slogan, "Where .COM meets .ORG", refers to its stated aim of bringing together commercial and non-commercial groups in the IT sector. Each year's event also had its own motto, often reflecting a specific topic which was focused in that year.

LinuxTag regards itself as part of the Free Software movement and hence promoted this community by an extraordinary degree through supporting numerous Open Source Software projects. LinuxTag offered these projects to promote their software and their concepts, and thus present themselves to the public in an appropriate manner, with their own booths, forums and lectures, free of charge. The goal is to encourage projects to share concepts and content to the benefit of other groups and companies, and to provide forums for in-depth discussions of new technologies and opportunities.

The non-profit association "LinuxTag e.V." was founded in preparation for LinuxTag's move from Kaiserslautern to the University of Stuttgart in 2000. The association plans and organizes the LinuxTag event by volunteer work and guides its ideological development. The association LinuxTag e.V. is registered in Association Register VR 2239 of the Kaiserslautern District Court. The association manages the LinuxTag name and word mark. The purpose of the association, according to its bylaws, is "the promotion of Free Software", and is pursued primarily by organizing the LinuxTag events.

The association is represented by a three-person executive board, supplemented by several representatives with delegated authority. All members of the LinuxTag association are volunteers and receive no remuneration for their service, with the sole exception from 1 April to 31 July 2005 when the First Chairman and CFO were employed and remunerated by the association. Surpluses resulting from the LinuxTag events or sponsorship are reinvested in the association's non-profit activities.

LinuxTag was launched in 1995 by a handful of active members of the "Linux project group (PG Linux)" of the Unix-AG, a student's workgroup at the University of Kaiserslautern. They wanted to inform the fellow students and the public about Linux and Open Source Software, which both were in their early stages at this time. However, since then the event has changed venues several times to keep pace with rapidly growing numbers of speakers, exhibitors and visitors.

The first couple of LinuxTag events were held at the University of Kaiserslautern and organized under the auspices of its Unix-AG PG Linux.

The very first LinuxTag in January 1996 was a theme night on Linux attended by 70 participants, comprising six talks and a "Linux install party".