Bertioga is a Brazilian municipality of the state of São Paulo in the Baixada Santista. It is part of the Metropolitan Region of Baixada Santista.
The population is 64,723 in an area of 490.15 km².
Because it neighbors resort towns, its population fluctuates greatly with the seasons. The more northern parts are dense forests and are virtually unpopulated. The municipality was created in May 19, 1991. Prior to that it was a part of Santos.
The municipality contains the 9,312 hectares Restinga de Bertioga State Park, created in 2010 to protect an area of mangroves, restinga and dense rainforest. Its limits are Mogi das Cruzes, Biritiba-Mirim and Salesópolis in the north, São Sebastião in the east, Atlantic Ocean to the south with Ilha de Santo Amaro and Santos in the west.
In 1979 Bertioga was the site of the death by drowning of Josef Mengele, a Nazi doctor at Auschwitz.