Monte San Giorgio is a mountain and UNESCO World Heritage Site on the border between Switzerland and Italy. It is part of the Lugano Prealps, overlooking Lake Lugano in the Swiss Canton of Ticino.

Monte San Giorgio is a wooded mountain, rising to 1,097 m (3,600 feet) above sea level. It has a roughly pyramidal shape, with a steep north edge sloping towards Lake Lugano and a more shallow South Slope extending towards the Po Plain. The eastern (Swiss) side of the mountain, between the municipalities of Brusino Arsizio, Riva San Vitale, and Meride, was listed as a World Heritage Site in 2003. This was in recognition of its cultural, biological, and especially paleontological significance. The site is renowned for its fossil content, one of the best known records of marine life in the Middle Triassic period. The Italian region west of Poncione d'Arzo (Porto Ceresio) was added as an extension to the World Heritage Site in 2010.