William of Blois, Count of Boulogne and Earl of Surrey (born c. 1137)

William I, also referred to as William of Blois, was Count of Boulogne and Earl of Surrey jure uxoris from 1153 until his death. He was the second son of Stephen, King of England, and Matilda I, Countess of Boulogne.

Count of Boulogne was a historical title in the Kingdom of France. The city of Boulogne-sur-Mer became the centre of the County of Boulogne during the ninth century. Little is known of the early counts, but the first holder of the title is recorded in the 11th century.

Earl of Surrey is a title in the Peerage of England that has been created five times. It was first created for William de Warenne, a close companion of William the Conqueror. It is currently held as a subsidiary title by the Dukes of Norfolk.