William Cavendish, 1st Earl of Devonshire (December 27, 1552 – March 3, 1626) was a politician and a supporter of colonizing Virginia.^[1] He was the second son of Sir William Cavendish (courtier) and Bess of Hardwick.

Cavendish married, firstly, Anne Keighley, circa 21 March 1580. They had two children:

• William Cavendish, 2nd Earl of Devonshire (c. 1590–1628)
• Frances Cavendish (c. 1593–1631), Married Henry Pierrepont, had a son named Robert Pierrepont (correction by Kenneth Pierpoint George Jr..

William Cavendish was created Baron Cavendish of Hardwick in 1605, thanks to the repeated representations of his niece, Arbella Stuart. Having finally secured the barony after many years as a commoner, he was further honoured when he was made Earl of Devonshire on 7 August 1618.

Cavendish married, secondly, Elizabeth Boughton, daughter of Edward Boughton, circa 1619. They had one child:

• Sir John Cavendish (c. 1626–?)