Louis III of Châtillon (died July 15, 1391) was the son of Guy II of Blois-Châtillon and Marie of Namur.
He married on May 29, 1386 in Bourges he married Marie, Duchess of Auvergne, daughter of John, Duke of Berry. However, they had no children, and his death left his father without heirs, causing him to sell Blois to Louis of Valois, Duke of Orléans.