An annotated check-list of the bryophytes of the Serra de Sintra is presented, based on a compendium of bibliographic records, on the revision of the material stored in Lisbon University herbarium (LISU) and Coimbra University herbarium (COI), as well as on the collections made by the authors during field work in 2011, 2013 and 2014. A total number of 279 taxa were recorded, out of which 5 taxa belong to Anthocerotophyta, 87 to Marchantiophyta and 187 to Bryophyta. Threat status in Portugal for taxa subject to conservation concern is also provided. The dominance of oceanic species on the other chorological types, as well as a remarkably high density of taxa per km² compared to other mountain regions in the Iberian Peninsula, is highlighted.