Jeremy George Weston "Jem" Marsh (born 15 April 1930 in Clifton, Bristol, England) is an engineer, motor manufacturer and race driver. He is perhaps best known as a co-founder of the sports-car manufacturer Marcos, the name being derived from a contraction of his and fellow founder Frank Costin's surnames. The company was continued by Jem's son Chris Marsh, until it was taken over by Canadian Tony Stellinga, and continued to produce automobiles until 2008 when it ceased production.