William de Warenne, 3rd Earl of Surrey (d. 1148), was the eldest son of the William de Warenne, 2nd Earl of Surrey and Elizabeth de Vermandois. He was thus a great-grandson of Henry I of France, and half-brother to Robert de Beaumont, 2nd Earl of Leicester, Waleran IV de Beaumont, Count of Meulan, and Hugh de Beaumont, 1st Earl of Bedford.

He was generally loyal to king Stephen. He fought at the Battle of Lincoln (1141), and was one of the leaders of the army that pursued the empress Matilda in her flight from Winchester, and which captured Robert of Gloucester.

He was one of the nobles that, along with Louis VII of France, took crusading vows at Vezelay in 1146, and he accompanied the initial army of the First Crusade the next year. He was killed by a Turkish attack while the army was marching across Anatolia on their way to the Holy Land.

William married Adela (or Ela), daughter of William Talvas, count of Ponthieu, who was the son of Robert of Bellême. They had one child, a daughter, Isabel, who was his heir. She married first William of Blois, second son of king Stephen, and who became earl of Warenne or Surrey. After he died without children in October 1159, she married Hamelin, half-brother of Henry II, who also became Earl of Warenne or Surrey. He took the de Warenne surname, and their descendents carried on the earldom.