Anavyssos is a town and a former municipality in East Attica, Greece located in the Athens Riviera. Since the 2011 local government reform it is part of the municipality Saronikos, of which it is a municipal unit. The municipal unit has an area of 14.478 km2. At the 2021 census it had 6,180 inhabitants. It is situated near the Saronic Gulf coast, at the foot of Olympos hill.