Melanie Jayne Marshall (born 12 January 1982) is a former British swimmer.
Born in Boston, Lincolnshire, brought up in Wrangle and currently residing in Loughborough with her two dogs, Missy and Jetson, she is 1.7 m (5′ 7″), 62 kg. A long lasting international career started at the 1995 European Youth Olympics in Bath, where she won four gold medals.
Marshall was ranked number one in the world in 2004 after breaking the British 200 m freestyle record to ensure selection to the 2004 Olympic Games in Athens.
At the 2008 Short Course World Championships in Manchester, she came third as part of the British women's 4×100 m freestyle relay team.
Marshall claimed six medals at the 2006 Commonwealth Games in Melbourne, and is currently the second most decorated female athlete ever. Marshall ended her swimming career at the 2008 Olympic Games in Beijing.
On 30 October 2008, Marshall announced her retirement from the sport. She was the head coach at City of Derby Swimming Club, where she first began coaching swimmers Commonwealth, European, World and Olympic champion Adam Peaty. Marshall has also worked as a coach with the British swimming team and has been named as an elite coach by UK Sport. In 2016 Marshall and Peaty both left City of Derby to join the University of Loughborough Swimming club.