São José do Barreiro (São José in Portuguese means Saint Joseph) is a municipality in the micro-region of Bananal in the eastern part of the state of São Paulo in Brazil. Both to the north and south it borders the state of Rio de Janeiro. It is part of the Metropolitan Region of Vale do Paraíba e Litoral Norte. The population is 4,185 (2015 est.) in an area of 570.69 km². The southern part of the municipality is part of the Serra da Bocaina National Park. Its main industries are cattle and tourism.