The House of Montlhéry was a noble family in medieval France, originating from the region of Île-de-France. Established in the 10th century, it played a significant role in the feudal system, with members often holding important titles and lands. The family is known for its connections to various other noble houses through marriage alliances. The most notable member was Guy de Montlhéry, who became a prominent figure in the 11th century. The house's influence waned over time, and by the 13th century, it had largely merged with other noble families, contributing to the complex tapestry of French nobility.