Wallach IX is a notable fictional planet in Frank Herbert's science fiction universe of Dune. Wallach is best known for being the site of the Mother School of the Bene Gesserit.

In the Legends of Dune trilogy Wallach was one of the Synchronized Worlds , and was given to Yorik Thurr after his defection from the human worlds. It was subsequently slagged by the fleet of the Butlerian Jihad.

This event is seen by some readers as being contradictory to its later role as home of the Bene Gesserit Mother School. However, the original series contain no description of conditions on Wallach IX, so it is completely possible that the Bene Gesserit have built their headquarters on a completely ruined and desolate planet. Alternatively, it is completely possible that natural ecological processes have reclaimed the planet in the ten thousand years between the Butlerian Jihad and the life of Paul Atreides.