John Hassell was an English watercolour landscape painter, engraver, illustrator, writer, publisher and drawing-master. He wrote a biography of fellow artist George Morland.

Hassell first appeared as an exhibitor at the Royal Academy, in London, in 1789 with a 'View of Stonehenge on Salisbury Plain.' He drew many views of local scenery, which he engraved himself in aquatint, most of them coloured. They were published in various topographical works. He had a large practice as a drawing-master and published some books on water-colour painting and drawing. Hassell was a friend of George Morland and wrote his biography (published in 1800); he also engraved Morland's drawing of 'Conway Castle' in aquatint.

His son Edward Hassell (d. 1852) was also a watercolourist, and exhibited for a number of years at the Society of British Artists, of which he became a member in 1841, and was also secretary. He occasionally exhibited at the Royal Academy and British Institution.