| Castrillo de Cabrera | |
| Native Name: | Castriellu de Cabreira |
| Native Name Lang: | ast |
| Pushpin Map: | Spain Castile and León#Spain |
| Coordinates: | 42.3403°N -6.5442°W |
| Subdivision Name3: | Castrillo de Cabrera |
| Leader Title: | Mayor |
| Leader Name: | Tomás Blanco Voces |
| Leader Party: | PSOE |
| Area Total Km2: | 115.87 |
| Elevation M: | 1051 |
| Population Density Km2: | auto |
| Utc Offset: | +1 |
| Utc Offset Dst: | +2 |
| Population Demonym: | cabreirés, cabreiresa |
| Postal Code Type: | Postal Code |
| Postal Code: | 24742 |
| Area Code Type: | Telephone prefix |
| Area Code: | 987 |
Castrillo de Cabrera (pronounced as /es/), Castriellu de Cabreira in Leonese language, is a municipality located in the province of León, Castile and León, Spain. According to the 2010 census (INE), the municipality has a population of 152 inhabitants spread over the six villages that make up the municipality. Those six villages are Castrillo de Cabrera, the municipal seat, Marrubio (Manrubiu), Noceda de Cabrera (Ñoceda de Cabreira), Nogar (Ñugare), Odollo (Udoyu) and Saceda (Saceda).
Leonese language is widely spoken in all the shire because of the isolation this area has experienced - and still does - through the years, making it easier for the language to survive than in other areas in the province of León.