William Henry Fitton (24 January 1780 – 13 May 1861) was an Irish physician and amateur geologist.
Having adopted the medical profession, he proceeded in 1808 to Edinburgh, where he attended the lectures of Robert Jameson, and thenceforth his interest in natural history and especially in geology steadily increased.
embodied a series of researches extending from 1824 to 1836, and form the memoir known as Fitton's Strata below the Chalk.
In this work he established the true succession and relations of the Upper and Lower Greensand, and of the Wealden and Purbeck formations, and elaborated their detailed structure.
His house then became a meeting place for scientific workers, and during his presidency he held a conversazione open on Sunday evenings to all fellows of the Geological Society.
From 1817 to 1841 he contributed to the Edinburgh Review many essays on the progress of geological science, and reviews of the groundbreaking books of William Smith (geologist), Charles Lyell, and Roderick Murchison; he also wrote Notes on the Progress of Geology in England for the Philosophical Magazine (1832–1833).