Hamelin de Warenne (d. April, 1202) was an English nobleman who was prominent at the courts of the Angevin kings of England, Henry II, Richard I, and John.

He was an illegitimate son of Geoffrey of Anjou, and thus a half-brother of Henry II, and an uncle of Richard I and John. Henry married him, in 1163/4, to Isabella de Warenne, in her own right Countess of Surrey. After the marriage he was recognized as Earl of Warenne, that being the customary designation for what more technically should be Earl of Surrey. In consequence of the marriage Hamelin took the de Warenne toponymic, as did his descendents.

Hamelin joined in the denunciations of Thomas Becket in 1164, although after Becket's death he became a great believer in Becket's sainthood, having, the story goes, been cured of blindness by the saint's help.

He remained loyal to Henry through all the problems of the later part of the king's reign when many nobles deserted him, and continued as a close supporter of his nephew Richard I. During Richard's absence on the Third Crusade he took the side of the regent William Longchamp.