Bellagio (Italian: [belˈlaːdʒo]; Comasco: Belàs [beˈlaːs]) is a comune (municipality) in the Province of Como in the Lombardy region of Italy. It is situated on Lake Como, known also by its Latin name Lario, where the lake's two southern arms branch, creating the Triangolo lariano. Bellagio's location at the tip of this promontory, looking out across the lake's northern arm towards the Alps, has long been noted for its scenic beauty. Bellagio is part of the Comunità montana del Triangolo lariano, headquartered in Canzo.

Traces of human presence around Bellagio date back to the Paleolithic period, approximately 30,000 years ago. Around the 7th to 5th centuries BC, a castellum (fortified hilltop settlement) may have existed on the promontory, potentially serving as a place of worship and trade for the scattered villages around the lake.