Louis III of Châtillon (died 1372), son of Louis II, Count of Blois and Jeanne of Hainault, was count of Blois and lord of Avesnes 1346 - 1372, and count of Soissons 1346 - 1367.
After the Battle of Poitiers, he had to send his brother Guy as a hostage to London, and ultimately sold Soissons to Enguerrand VII de Coucy to ransom him.