Castellcir is a village and municipality in the province of Barcelona, in the autonomous community of Catalonia, Spain. It covers an area of 34.2 square kilometres (13.2 sq mi) and had a population of 718 in 2014.
The municipality includes an exclave to the west, separated from the main body of the municipality. Since May 2015 it has formed part of the new comarca of Moianès; before that change it belonged to the comarca of Vallès Oriental.