Henry Spencer, 1st Earl of Sunderland, 3rd Baron Spencer of Wormleighton, known as The Lord Spencer between 1636 and June 1643, was an English peer, nobleman, and politician from the Spencer family who fought and died in the English Civil War on the side of the Cavaliers.

The Spencer family is an aristocratic family in the United Kingdom. From the 16th century, its members have held numerous titles, including the dukedom of Marlborough, the earldoms of Sunderland and Spencer, and the Churchill barony. Two prominent members of the family during the 20th century were Sir Winston Churchill and Diana, Princess of Wales.