Charles Spencer, 3rd Duke of Marlborough,, styled as The Honourable Charles Spencer between 1706 and 1729 and as the Earl of Sunderland between 1729 and 1733, was a British soldier, nobleman, and politician from the Spencer family. He briefly served as Lord Privy Seal in 1755. He led British forces during the Raid on St Malo in 1758.

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.