William Cavendish, 2nd Duke of Devonshire was a British nobleman and politician. He was the eldest son of William Cavendish, 1st Duke of Devonshire and Lady Mary Butler. A prominent Whig, he was sworn of the Privy Council in 1707, and served as Lord President of the Council from 1716 to 1718 and 1725 to 1729.

William Cavendish, 1st Duke of Devonshire, was an English Army officer, Whig politician and peer who sat in the House of Commons from 1661 until 1684 when he inherited his father's peerage as Earl of Devonshire and took his seat in the House of Lords. Cavendish was part of the "Immortal Seven" which invited William of Orange to depose James II of England as part of the Glorious Revolution, and was rewarded for his efforts by being elevated to the Duke of Devonshire in 1694.