FET

FET is open source free software for automatically scheduling the timetable of a school, high-school or university. It uses a fast and efficient timetabling algorithm. It is licensed under GNU/GPL

http://www.lalescu.ro/liviu/fet/

Tablix

Tablix is a Free software for solving timetabling problemspowerful free software kernel implementing a parallel genetic algorithm. It can be used to solve a large subset of discreet multivariable optimization problems, but is specially optimized for timetabling. Because of its modular design it is relatively simple to adapt Tablix to needs of a specific organization. Coarse-grained parallel algorithm can also fully exploit any multi-processor machine that supports PVM3 - from modern multi-core CPUs to clusters of low-end machines connected by a local area network. Specifically this means most users will want to use Tablix on Linux or another UNIX-like operating system.

https://www.tablix.org/articles/about/

Intime

This is a free, open source program for editing school time tables.

Using drag and drop in a graphic user interface you assign teachers, time slots and rooms to a given set of lessons (read more, look at screenshots).

http://intime.sourceforge.net/

TimeFinder

TimeFinder is a free software which automatically optimizes schedules of schools and universities. The algorithm is able to optimize the timetable of hundreds of events and persons within minutes. Manual timetabling for the human timetabler will be easier via a graphical user interface. The calendar component shows all events of a person and gives a good overview of the current timetable. Data can be exported and imported in xml and text formats.

http://timefinder.sourceforge.net/ [Not Maintained Any Longer]