| Capitán Sarmiento | |
| Native Name: | Partido de Capitán Sarmiento |
| Settlement Type: | Department |
| Coordinates: | -34.1833°N -105°W |
| Subdivision Type: | Country |
| Subdivision Name: | Argentina |
| Established Title: | Established |
| Established Date: | December 12, 1961 |
| Founder: | Provincial law 2959 |
| Seat Type: | Seat |
| Seat: | Capitán Sarmiento |
| Leader Party: | Partido Vecinal |
| Leader Title: | Mayor |
| Leader Name: | Francisco Álvarez |
| Unit Pref: | Metric |
| Area Total Km2: | 617 |
| Population Total: | 12854 |
| Population Density Km2: | auto |
| Population Demonym: | sarmientense |
| Postal Code Type: | Postal Code |
| Postal Code: | B2752 |
| Postal2 Code Type: | IFAM |
| Postal2 Code: | BUE019 |
| Area Code Type: | Area Code |
| Area Code: | 02478 |
| Blank Name Sec1: | Patron saint |
| Blank Info Sec1: | San Carlos Borromeo |
| Website: | http://www.capitansarmiento.gov.ar/ |
Capitán Sarmiento Partido is a partido of Buenos Aires Province in Argentina.
The provincial subdivision has a population of around 12,500 inhabitants in an area of 617sqkm, and its capital city is Capitán Sarmiento, which is around 160km (100miles) from Buenos Aires.
The city of Capitán Sarmiento gradually built up around a railway station between San Antonio de Areco and Pergamino. The railway station was named in honour of Domingo Fidel Sarmiento, (adopted son of Domingo Faustino Sarmiento), who died in the Battle of Curupaytí in the Paraguayan War. The town and eventually the partido became known by the same name as the train station.