The Medieval Merchant's House is a restored late-13th-century building in Southampton, Hampshire, England. Built in about 1290 by John Fortin, a prosperous merchant, the house survived many centuries of domestic and commercial use largely intact. German bomb damage in 1940 revealed the medieval interior of the house, and in the 1980s it was restored to resemble its initial appearance and placed in the care of English Heritage, to be run as a tourist attraction. The house is built to a medieval right-angle, narrow plan design, with an undercroft to store wine at a constant temperature, and a first-storey bedchamber that projects out into the street to add additional space. The building is architecturally significant because, as historian Glyn Coppack highlights, it is "the only building of its type to survive substantially as first built"; it is a Grade I listed building and scheduled monument.