John Kidd (September 10, 1775 - September 7, 1851) was an English physician, chemist and geologist.

John Kidd was born in Westminster, the son of a naval officer. He was educated at Christ Church, Oxford. He became reader in chemistry at Oxford in 1801, and in 1803 was elected the first Aidrichian professor of chemistry. He then voluntarily gave courses of lectures on mineralogy and geology: these were delivered in the dark chambers under the Ashmolean Museum, and there William Conybeare, William Buckland, Charles Daubeny and others gained their first lessons in geology. Kidd was a popular and instructive lecturer, and through his efforts the geological chair, first held by Buckland, was established. In 1818 he became a fellow of the Royal College of Physicians; in 1822 regius professor of medicine in succession to Sir Christopher Pegge; and in 1834 he was appointed keeper of the Radcliffe Library. He delivered the Harveian oration before the Royal College of Physicians in 1834.

Publications: Outlines of Mineralogy (1809); A Geological Essay on the Imperfect Evidence in Support of a Theory of the Earth (1815); On the Adaptation of External Nature to the Physical Condition of Man (1833).