Marchwood Military Port (MMP) or Marchwood Sea Mounting Centre (SMC) is a military port located in Marchwood, Southampton on the south coast of the UK, and the base of 17 Port & Maritime Regiment Royal Logistic Corps. The port was built in 1943 to aid in the D-Day assault on Normandy in 1944 and has since been used to support the Falklands War. The port is now used largely by the Royal Fleet Auxiliary, as a base for their ships, including the Tide-class tankers, and it is also still employed for military cargo and personnel movement.

Marchwood is a village and civil parish located in Hampshire, England. It lies between Totton and Hythe on the western shore of Southampton Water and directly east of the New Forest. The population of the village in the 2011 census was 6,141.