| Settlement Type: | municipality |
| Official Name: | O Pereiro de Aguiar |
| Pushpin Map: | Spain |
| Pushpin Map Caption: | Location in Spain |
| Coordinates: | 42.3464°N -7.8003°W |
| Subdivision Type: | Country |
| Subdivision Name: |  Spain |
| Subdivision Type1: | Autonomous community |
| Subdivision Type2: | Province |
| Subdivision Type3: | Comarca |
| Subdivision Name3: | Ourense |
| Area Total Km2: | 60.9 |
| Area Footnotes: | [1] |
| Elevation M: | 321 |
| Population Density Km2: | auto |
| Timezone: | CET |
| Utc Offset: | +1 |
| Timezone Dst: | CEST |
| Utc Offset Dst: | +2 |
| Leader Title: | Mayor |
| Leader Name: | Eliseo Fernández Gómez |
| Leader Party: | People's Party |
| Postal Code Type: | Postal Code |
| Postal Code: | 32710 |
O Pereiro de Aguiar is a small municipality in the province of Ourense, in the autonomous community of Galicia, Spain. It belongs to the comarca of Ourense.