William Cavendish, 1st Earl of Devonshire was an English nobleman, politician, and courtier.

Sir William Cavendish MP was an English politician, knight and courtier. Cavendish held public office and accumulated a considerable fortune, and became one of Thomas Cromwell's "visitors of the monasteries" during the dissolution of the monasteries. He was MP for Thirsk in 1547. In 1547 he married Bess of Hardwick, and the couple began the construction of Chatsworth House in 1552, a project which would not be completed until after his death. His second son William Cavendish (1552–1626) became the first Earl of Devonshire, purchasing his title from the impecunious King James I.