Henry Boyle, 1st Earl of Shannon, PC (Ire) (1682 – 28 December 1764) was a prominent Irish politician.
Boyle was the second son of Lieutenant-Colonel Henry Boyle (1648–1693), second son of Roger Boyle, 1st Earl of Orrery. His mother was Lady Mary O'Brien, daughter of Murrough O'Brien, 1st Earl of Inchiquin. In, 1707, he was elected to the Irish House of Commons for Midleton, a seat he held until 1713, and then sat for Kilmallock from 1713 to 1715. Between 1715 and 1756 he represented County Cork. He quickly gained a prominent role in Parliament and Sir Robert Walpole is said to have styled him "the King of the Irish House of Commons". In 1733 Boyle was admitted to the Irish House of Commons and appointed Chancellor of the Irish Exchequer. Later that year he was also made Speaker of the Irish House of Commons. His career was marked by a long struggle for power with George Stone, Archbishop of Armagh, which only ended with their death in the same week. He deserves some credit for helping to organise measures to alleviate the terrible Irish Famine (1740–41) which became known as "the year of slaughter".
He held these posts until 1753, when he was dismissed by the viceroy Lord Dorset for refusing to pay over an Irish tax surplus to the government in London. This led to the "Money Bill dispute" of 1753-56, and Boyle came to be seen as an early Irish patriot. Reinstated in 1755 by Devonshire, the next viceroy, in 1756 he was raised to the Peerage of Ireland as Baron Castle Martyr, Viscount Boyle, of Bandon, and Earl of Shannon. He also acted several times as Lord Chief Justice of Ireland.
Horace Walpole dismissed him as a "common character" who sold his patriotism for a peerage.
Lord Shannon married, firstly, Catherine, daughter of Chidley Coote, in 1715. After her death in 1725 he married, secondly, Lady Henrietta Boyle, youngest daughter of Charles Boyle, 3rd Earl of Cork and 2nd Earl of Burlington, in 1726. Lord Shannon died in December 1764, in his 82nd year, and was succeeded in his titles by his son from his second marriage, Richard.