The House of Montfort was a medieval French noble house that eventually found its way to the Kingdom of England and originated the famous Simon de Montfort, 6th Earl of Leicester.

The family began when Hugh Capet granted a petty lordship to Guillaume de Montfort in the Île-de-France.

Guillaume's son, Amaury began building a castle that would eventually become the eponymous Montfort-l'Amaury.

The project, however, was incomplete when he died c. 1053, but his son, Simon, finished it in 1067.

[1] During the 13th century the family lost its ancestral seat of Montfort-l'Amaury to the House of Dreux.