Dorothy Bentinck, Duchess of Portland

Her Grace The Duchess of Portland
Dorothy Bentinck, Duchess of Portland by George Romney
Tenure	8 November 1766 – 3 June 1794
Born	(1750-08-27)27 August 1750
Died	3 June 1794(1794-06-03) (aged 43) London, England
Buried	St Marylebone Parish Church
Spouse(s)	William Cavendish-Bentinck, 3rd Duke of Portland ​ ​ (m. 1766)​
Issue	9, including: William Bentinck, 4th Duke of Portland Lord William Bentinck Lord Charles Bentinck
Father	William Cavendish, 4th Duke of Devonshire
Mother	Charlotte Boyle, 6th Baroness Clifford

Dorothy Bentinck, Duchess of Portland (née Lady Dorothy Cavendish; 27 August 1750 – 3 June 1794) was Duchess of Portland and the wife of William Cavendish-Bentinck, 3rd Duke of Portland, the Prime Minister of Great Britain.