Philip de Montmorency (1524 - 5 June 1568, Brussels) is also known as Count of Horn or Hoorne.

De Montmorency is born between 1518 and 1526, possibly at the Ooidonk Castle, as the son of Jozef van Montmorency, Count of Nevele and Anna van Egmont.

His father dies in 1530 in Italy, and his mother remarries Johan II, Count of Horn, from which Philip inherits the County of Horne in 1540.

A page and later chamberlain at the court of Charles V, he marries Walburgis of Neuenahr in 1546.

He becomes stadtholder of Guelders (Dutch: Gelderland) in 1555, an Admiral of Flanders (Dutch: Vlaanderen), and a knight of the Golden Fleece (Dutch: Orde van het Gulden Vlies) in 1556.