James Hargreaves was a British inventor and industrialist. In 1764, while working as a weaver at Stanhill, Lancashire, England, he invented the spinning jenny. This greatly speeded the spinning process of cotton by producing eight threads at once. In 1768 local spinners, fearing that Hargreaves and his machines threatened their jobs, destroyed his house and equipment. Hargreaves fled to Nottingham, where he patented the jenny (1770) and, with Thomas James, built a spinning mill and became one of the first great factory owners. In 1777 he adopted Richard Arkwright's more sophisticated machine.

See also Crompton, Samuel.