John Sell Cotman (16 May 1782 – 24 July 1842) was an English marine and landscape painter, etcher, illustrator, and a leading member of the Norwich School of painters.
Born in Norwich, the son of a silk merchant and lace dealer, Cotman was educated at the Norwich Grammar School. He showed an early talent for art. It was intended that he followed his father into the family business but, intent on a career in art, he moved to London in 1798, where he met artists such as J. M. W. Turner, Peter de Wint and Thomas Girtin, whose sketching club he joined, and whom he travelled with to Wales and Surrey. By 1800 he was exhibiting at the Royal Academy, showing scenes of the Welsh countryside there in 1801 and 1802. His drawing expeditions took him throughout southern Britain, and to Yorkshire, where he stayed with the Cholmeley family during the three summers of 1803–1805.
His sons Miles Edmund and John Joseph Cotman became notable painters in their own right.