Santa Bárbara d'Oeste is a municipality in the State of São Paulo in Brazil. It is part of the Metropolitan Region of Campinas. It lies about 138 kilometres northwest of the State capital. It occupies an area of 272.2 square kilometres, of which 43.1 square kilometres is urban. In 2020, the population was estimated at 194,390 by the Brazilian Institute of Geography and Statistics, making it the 43rd most populous city in São Paulo and the sixth largest in the metropolitan region of Campinas.