Sir Henry Cavendish, 2nd Baronet PC (29 September 1732 – 3 August 1804) was an Anglo-Irish politician noted for his extensive recording of parliamentary debates in the late 1760s and early 1770s.
Cavendish was the son of Sir Henry Cavendish, 1st Baronet, and his wife Anne (née Pyne), daughter of Sir Richard Pyne, Lord Chief Justice of Ireland. This branch of the Cavendish family descended from Henry Cavendish, illegitimate son of Henry Cavendish of Tutbury Prior, eldest son of Sir William Cavendish and Bess of Hardwick and elder brother of William Cavendish, 1st Earl of Devonshire (the ancestor of the Dukes of Devonshire).
He sat in the Irish House of Commons for Lismore from 1766 to 1768 and from 1776 to 1791 (when he was declared not duly elected in the 1790 election). He instead represented Killybegs from 1791 to 1797, also serving as Vice-Treasurer of Ireland and as Receiver-General in Ireland. In 1779 he was admitted to the Irish Privy Council. He again represented Lismore from 1798 to the Act of Union in 1800/01. Cavendish was also a member of the British House of Commons for Lostwithiel between 1768 and 1774.
He is chiefly remembered for the enormous amounts of notes he took of the debates in this session of Parliament using Gurney's system of shorthand. The 1768 to 1774 Parliament has otherwise been termed the unreported Parliament, making Cavendish's notes an important historical source. During this time the reporting of parliamentary debates was forbidden. The notes, which include speeches by Edmund Burke, George Grenville, Lord North and Charles James Fox, are now stored in the British Museum.