| Horcajo de la Sierra | |
| Settlement Type: | Municipality |
| Pushpin Label Position: | above |
| Pushpin Map Caption: | Location in Spain |
| Subdivision Type: | Country |
| Subdivision Name: |  Spain |
| Subdivision Type1: | Autonomous community |
| Subdivision Name1: | Community of Madrid |
| Subdivision Type2: | Province |
| Subdivision Name2: | Madrid |
| Subdivision Type3: | Comarca |
| Subdivision Name3: | Sierra Norte de Madrid |
| Leader Title: | Mayor |
| Leader Name: | Raúl Andrés Martín |
| Area Total Km2: | 21.2 |
| Population Density Km2: | auto |
| Population Blank1 Title: | Ethnicities |
| Utc Offset: | +1 |
| Utc Offset Dst: | +2 |
| Coordinates: | 41.0681°N -3.5858°W |
| Elevation M: | 1068 |
| Postal Code: | 28755 |
Horcajo de la Sierra (pronounced as /es/) is a municipality of the Community of Madrid, Spain.