Jacob ben Machir ibn Tibbon, of the Ibn Tibbon family, also known as Prophatius is a Provençal Jewish astronomer; born, probably at Marseilles, about 1236; he dies at Montpellier about 1304.

He is a grandson of Samuel ben Judah ibn Tibbon.

His Provençal name is Don Profiat Tibbon; the Latin writers call him Profatius Judæus.

Jacob occupies a considerable place in the history of astronomy in the Middle Ages.

His works, translated into Latin, are quoted by Copernicus, Reinhold, and Clavius.

He is also highly reputed as a physician, and, according to Jean Astruc ("Mémoires pour Servir à l'Histoire de la Faculté de Médecine de Montpellier," p. 168), was regent of the faculty of medicine of Montpellier.