William married Georiana Spencer in 1774 in Wimbledon, Surrey, , England. Georiana (daughter of Baron Spencer of Althop John (1st Earl Spencer) Spencer and Margaret Georgiana Poyntz) was born on 7 June 1757 in Althorp, Daventry District, Northamptonshire, England; died on 30 March 1806 in Piccadilly, London, England; was buried in Derby, Derby Unitary Authority, Derbyshire, England. [Group Sheet] [Family Chart]

1. Georgiana Dorothy Cavendish was born on 12 Jul 1783 in Hardwick, Suffolk, , England; died on 8 Aug 1858 in Castle Howard, Yorkshire, , England.
2. Harriet Elizabeth Cavendish was born on 29 Aug 1785 in Hardwick, Suffolk, , England; died on 25 Nov 1862 in London, Middlesex, , England.
3. William ( 6th Duke of Devonshire) Cavendish was born on 21 May 1790 in Passy, Paris, Ile-de-France, France; died on 17 Jan 1858 in Hardwick Hall, Derbyshire, , England.
4. Eliza Courtenay was born on 21 Feb 1792 in Montpellier, St Croix, Virgin Islands (US), USA; died in 1859.

William married Charlotte Elizabeth Boyle. Charlotte was born on 27 Oct 1731 in Barrowby, Lincolnshire, , England; died on 8 Dec 1754 in Uppingham, , Rtlnd, England. [Group Sheet] [Family Chart]