| Settlement Type: | City |
| Official Name: | Olavarría |
| Pushpin Map1: | Buenos Aires Province |
| Pushpin Label Position1: | bottom |
| Pushpin Map Caption1: | Location in Buenos Aires Province |
| Pushpin Mapsize1: | 200 |
| Subdivision Type: | Country |
| Subdivision Type1: | Province |
| Subdivision Name1: | Buenos Aires |
| Subdivision Type2: | Partido |
| Subdivision Name2: | Olavarría |
| Established Title: | Founded |
| Established Date: | 25 November 1867 |
| Area Total Km2: | 7715 |
| Population Total: | 111320 |
| Population Density Km2: | auto |
| Coordinates: | -36.9°N -80°W |
| Elevation M: | 162 |
| Postal Code Type: | CPA Base |
| Postal Code: | B 7400 |
| Area Code: | +54 2284 |
| Website: | Official website |
Olavarría is a city in the province of Buenos Aires, Argentina. It is the administrative seat of the Olavarría Partido and has over 111,320 inhabitants, per the .
The settlement was officially founded on 25 November 1867, and named in honour of Colonel José Valentín de Olavarría (1801–1845), an early Argentine military leader.