Guillaume de Montfort of Hainaut

Guillaume de Montfort, also known as Guillaume of Hainaut, was a French nobleman of the end of the 10th century, the first Lord of Montfort-l'Amaury.

He was succeeded as Lord of Montfort-l'Amaury by his son Amaury I de Montfort.

Guillaume is possibly the son of Amaury, Count of Valenciennes.