Guy III, Count of Saint-Pol

Guy III of Châtillon, Count of Saint-Pol (died 1289) was a French nobleman, and a younger son of Hugh I, Count of Blois, and Mary, Countess of Blois.

While his elder brother John I of Châtillon succeeded to their mother's County of Blois, Guy was given their father's county of Saint-Pol-sur-Ternoise at his death in 1248.

On January 16, 1255, Guy married Matilda of Brabant, Countess of Artois, daughter of Henry II, Duke of Brabant and Marie of Swabia, and thereafter was a supporter of his brother-in-law Henry III against Guelders. They had: Guy IV, Count of Saint-Pol Hugh II, Count of Blois. Jacques, lord of Leuze-Châtillon. Beatrix (d. 1304), married John I of Brienne, Count of Eu Jeanne, married Guillaume III de Chauvigny, Lord of Châteauroux Gertrude, married Florent, Lord of Mechelen

Guy joined the Eighth Crusade (1270) and the ill-fated Crusade of Aragón of Philip III of France.