Augustus Henry FitzRoy, 3rd Duke of Grafton (28 September 1735 – 14 March 1811), styled Earl of Euston between 1747 and 1757, was a British Whig statesman of the Georgian era. He is one of a handful of dukes who have served as Prime Minister.
He became Prime Minister in 1768 at the age of 33, leading the supporters of William Pitt, and was the youngest person to have held the office until the appointment of William Pitt the Younger 15 years later. However, he struggled to demonstrate an ability to counter increasing challenges to Britain's global dominance following the nation's victory in the Seven Years' War. He was widely attacked for allowing France to annex Corsica, and stepped down in 1770, handing over power to Lord North.