San Cebrián de Castro is a municipality in the province of Zamora, within the autonomous community of Castile and León, Spain. It is located in the northwestern part of the country, in a region characterised by a continental Mediterranean climate and a landscape of rolling plains and farmland typical of the Duero basin.
According to the 2004 census conducted by Spain's National Statistics Institute (INE), the municipality had a population of 337 inhabitants. Like many small rural municipalities in the Castile and León region, San Cebrián de Castro is sparsely populated, with its residents distributed across the municipal territory and its surrounding hamlets.
The municipality forms part of the comarca of Tierra del Pan, an agricultural area centred on the city of Zamora. Its economy and settlement patterns reflect the broader demographic and rural character of the province, which is one of the least densely populated areas of Spain.