Cayey, officially Cayey de Muesas, is a mountain town and municipality in central Puerto Rico located on the Sierra de Cayey within the Central Mountain range, north of Salinas and Guayama; south of Cidra and Caguas; east of Aibonito and Salinas; and west of San Lorenzo. Cayey is spread over 21 barrios plus Cayey Pueblo. It is part of the San Juan-Caguas-Guaynabo Metropolitan Statistical Area.

Cayey barrio-pueblo is a barrio and the administrative center (seat) of Cayey, a municipality of Puerto Rico. Its population in 2010 was 15,298.