James Garth Marshall (20 February 1802 – 22 October 1873) was an English Liberal Party politician, the Member of Parliament for Leeds (1847–1852). He was the third son of the wealthy industrialist John Marshall who introduced major innovations in flax spinning and built the celebrated Marshall's Mill and Temple Works in Leeds, West Yorkshire. His eldest brother William was MP for Beverley, Carlisle and East Cumberland and his next eldest brother, John, was an earlier MP for Leeds. The fourth brother, Henry Cowper, was Mayor of Leeds in 1842–1843.