Southdown Motor Services Ltd operates bus and coach services in East and West Sussex and parts of Hampshire, in southern England. It was formed in 1915 and had various owners throughout its history, being purchased by the National Bus Company (NBC) in 1969. The company fleet name was lost when it was acquired by the Stagecoach Group in 1989 but continues as the legal name of Stagecoach in the South Downs, part of Stagecoach South.