| San Sossio Baronia | |
| Official Name: | Comune di San Sossio Baronia |
| Coordinates: | 41.0667°N 27°W |
| Province: | (AV) |
| Frazioni: | Civita, Molara, Montuccio, Turro, Montemauro |
| Mayor: | Giovanni Contardi |
| Area Total Km2: | 19.19 |
| Population Total: | 1598 |
| Population As Of: | 31 December 2017[1] |
| Population Demonym: | Sossiani |
| Elevation M: | 650 |
| Saint: | St. Sossius |
| Postal Code: | 83050 |
| Area Code: | 0827 |
San Sossio Baronia is a town and comune in the province of Avellino, Campania, Italy. Its name refers to Saint Sossius, a Roman Catholic martyr.
Located in the Apennines between the Ufita Valley and Daunian Mountains, the town is part of the Roman Catholic Diocese of Ariano Irpino-Lacedonia. Its territory borders the municipalities of Anzano di Puglia (FG), Flumeri, Monteleone di Puglia (FG), San Nicola Baronia, Trevico, Vallesaccarda and Zungoli.