Field Marshal George Hay, 8th Marquess of Tweeddale, KT, GCB (February 1, 1787 - October 10, 1876) was a Scottish soldier and administrator who rose to the rank of Field Marshal in the British Army.

Hay was born in Bonnington, Angus in 1787, and educated at the Royal High School, Edinburgh. He succeeded his father (who had been imprisoned until his death by Napoleon in France) as Marquess of Tweeddale in 1804 and fought in the Anglo-American War of 1812 as lieutenant colonel of the 100th Regiment of Foot.

On 28 March 1816, Lord Tweeddale married Lady Susan Montagu (a younger daughter of the 5th Duke of Manchester) and they had fourteen children:

• Lady Susan Georgiana (1817-1853), married the 1st Marquess of Dalhousie and had issue.
• Lady Hannah Charlotte (1818-1887), married Simon Taylor and had issue.
• Lady Louisa Jane (1819-1882), married Robert Ramsay and had issue.
• Lady Elizabeth (1820-1904), married the 2nd Duke of Wellington.
• George, Earl of Gifford (1822-1862)
• Lady Millicent (1823-1826), died young.
• Lord Arthur, later Earl of Gifford and later 9th Marquess of Tweeddale (1824-1878)
• Lord William Montagu, later 10th Marquess of Tweeddale (1826-1911)
• Lord John (1827-1916)
• Lady Jane (1830-1920), married Sir Richard Taylour and had issue.
• Lady Julia (1831-1915)
• Lord Charles Edward (1833-1912)
• Lord Frederick (1835-1912)
• Lady Emily (1836-1924), married Sir Robert Peel, 3rd Baronet and had issue.

Lord Tweeddale was admitted to the Order of the Thistle as a knight in 1820. Professionally, Tweeddale rose to the rank of Field Marshal in the army and was Governor of Madras in India.

He died in 1876 at Yester in Scotland, and is buried there.