Cantalejo is a municipality in the province of Segovia, within the autonomous community of Castile and León, Spain. It is located in the central part of the country, in the region north of the Sierra de Guadarrama.
According to the 2023 census conducted by Spain's National Statistics Institute (INE), the municipality had a population of 3,546 inhabitants.
Cantalejo is notable for being a place where the dialect known as Gacería is spoken. Gacería is a distinct linguistic variety associated with the area.