The Grotte de Mongautin is an ornate cave located on the territory of the commune of Prat-Bonrepaux in the department of Ariège, in France.

Discovered in 1996, it has yielded archaeological remains dating from the Upper Paleolithic and has been listed as a historic monument since 1999.

In the immediate vicinity opens the cave of Peyort with beautiful rooms and superb stalactites, also decorated with rock engravings.