Castiello de Jaca is a municipality in the province of Huesca, in the Aragon region of Spain. It lies in the Pyrenean area of northern Aragon, near the town of Jaca.
According to the 2004 census (INE), the municipality had a population of 198 inhabitants. Recent developments have seen the size of the town increase greatly. It is serviced by the Jaca-Astun bus, and there are two restaurants or bars in the municipality.