Sant Martí de Centelles is a municipality in the comarca of Osona, in the autonomous community of Catalonia, Spain. It lies in the province of Barcelona, within the inland part of Catalonia.
The municipality is situated in the Osona district, a comarca of central Catalonia that lies between the coastal plain and the Pyrenean foothills. As a municipality, Sant Martí de Centelles forms part of the local administrative structure of the region.
Its name derives from its patron saint, Martin, and it is one of several places in Catalonia bearing the name Sant Martí. The settlement is distinct from other municipalities of similar name elsewhere in the region.