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.

Duke of Devonshire is a title in the Peerage of England held by members of the Cavendish family. This branch of the Cavendish family has been one of the wealthiest British aristocratic families since the 16th century and has been rivalled in political influence perhaps only by the Marquesses of Salisbury and the Earls of Derby.