1765 in Great Britain

Incumbents

• Monarch – George III
• Prime Minister – George Grenville ; Charles Watson-Wentworth, 2nd Marquess of Rockingham

Events

• January–April – George III suffers a malady, perhaps a first manifestation of bipolar disorder.
• 8 February – Nevil Maskelyne becomes Astronomer Royal.
• 22 March – Parliament passes the Stamp Act which is the first direct tax levied on the American colonies.
• 24 March – Parliament passes the Quartering Act that requires the 13 American colonies to house British troops.
• 7 May – is launched at Chatham Dockyard; at the beginning of the 21st century it remains the oldest naval ship still in commission.
• May – James Watt makes a breakthrough in the development of the steam engine by constructing a model with a separate condenser.
• 21 June – the Isle of Man is brought under British control, the Isle of Man Purchase Act confirming HM Treasury's purchase of the feudal rights of the Dukes of Atholl as Lord of Mann over the island and revesting them into the British Crown.
• 12 July – George Grenville is dismissed as Prime Minister by King George III.
• 13 July – Charles Watson-Wentworth, 2nd Marquess of Rockingham succeeds Grenville as Prime Minister.
• 7 August – armed mutiny at Maidstone County Gaol.
• 12 August – Robert Clive secures the rights for the East India Company to collect taxes in Bengal from Mughal Emperor Shah Alam II.
• 2 November – the decision of the King's Bench in Entick v Carrington establishes the civil liberties of individuals and limiting the scope of executive power.

Undated

• Lord Mansfield decides the landmark case of Pillans v Van Mierop in English contract law in relation to the doctrine of consideration.
• Taylors & Lloyds Bank established in Birmingham.
• Kedleston Hall in Derbyshire completed.
• William Tryon appointed Governor of North Carolina.

Publications

• William Blackstone's influential work Commentaries on the Laws of England begins publication.
• Thomas Percy's ballad collection Reliques of Ancient English Poetry.The History of Little Goody Two-Shoes, an anonymous children's story published by John Newbery.Mother Goose's Melody, or, Sonnets for the Cradle, a collection of nursery rhymes published by John Newbery .

Births

• 2 January – Charles Hatchett, chemist
• 13 January – Richard Westall, painter
• 26 April – Emma, Lady Hamilton, born Amy Lyon, mistress of Horatio Nelson
• 15 June – Henry Thomas Colebrooke, orientalist
• 27 July – John Marshall, textile manufacturer
• 21 August – King William IV
• 24 October – James Mackintosh, Scottish-born journalist, judge, administrator, professor, philosopher and Whig politician
• 20 November – Thomas Fremantle, admiral and politician
• Approximate date – James Smithson, chemist, mineralogist and posthumous founder of the Smithsonian Institution in the United States, born in France

Deaths

• 3 March – William Stukeley, archaeologist
• 5 April – Edward Young, poet
• 10 October – Lionel Sackville, 1st Duke of Dorset, Lord Lieutenant of Ireland
• 31 October – Prince William, Duke of Cumberland, military leader
• 30 November – George Glas, merchant and adventurer
• 3 December – Lord John Philip Sackville, cricketer