Gith are a race of psionic creatures. Typically they are used as slaves though they are normally found in tribes. They are one of the more common races.
Gith are hunched creatures that typically are around a little over 5 feet tall. If they stood up they would easily hit 7 feet. They have four long fingers.
Gith are descendants of the Githyanki. In a bid to conquer Athas they create various strongholds that could only be accessed via Plane Shift spells. In a coordinated attack the Githzerai managed to activate a psionic super weapon. The end result was that the Githyanki's minds were so scarred that they forgot who they were and their psionic abilities were severally damage, and thus the Gith were born.
Walter Baas (February 1994). DSE2: Black Spine (Dark Sun). TSR, Inc. ISBN 1-56076-824-X. Bruce R. Cordell (August 2010). Dark Sun Creature Catalog. Wizards of the Coast. ISBN 0-7869-5495-7.