Henry Gally Knight, F.R.S. (2 December 1786 – 9 February 1846) was a British M.P., traveller and writer.
He was the only son of Henry Gally (afterwards Gally Knight), barrister, of Langold, and was educated at Eton and Trinity Hall, Cambridge. He succeeded in 1808 to estates at Firbeck and Langold Park which his father had inherited in 1804 from his brother John Gally Knight.
He was appointed High Sheriff of Nottinghamshire for 1814–15.
He was the author of several Oriental tales, Ilderim, a Syrian Tale (1816), Phrosyne, a Grecian Tale, and Alashtar, an Arabian Tale (1817). He was also an authority on architecture, and wrote various works on the subject, including The Ecclesiastical Architecture of Italy, Hannibal in Bithynia and The Normans in Sicily, which brought him more reputation than his fictions. He was the nephew of the novelist Frances Jacson.
His best claim to fame may be the satirical poem "Ballad to the Tune of Salley in our Alley" by Lord Byron, in which Byron facetiously accuses him of being not only a poetaster, but a dandy as well.
He owned Firbeck Hall in Rotherham. Sir Walter Scott's novel Ivanhoe is set nearby, and Knight may have been Scott's source of local information when he was writing the book. He was admitted a Fellow of the Royal Society on 20 May 1841.
He married Henrietta, the daughter of Anthony Hardolph Eyre of Grove Park, Nottinghamshire and the widow of John Hardolph Eyre. They had no children.