Mahaut of Châtillon (1293– 3 October 1358) was the daughter of Guy IV of Châtillon, Count of Saint-Pol and Marie of Brittany, daughter of John II, Duke of Brittany.

In 1308 she married Charles, Count of Valois,[1] the third son of King Philip III of France and Isabella of Aragon.

[2] He was also the younger brother of King Philip IV.

One of their daughters would make them ancestors of French kings, and another daughter would become Queen of Germany.

Mahaut died 33 years later in 1358 at the age of 65, having outlived three of her four children; only her second daughter Isabella outlived her.