| Piennes-Onvillers | |
| Commune Status: | Commune |
| Arrondissement: | Montdidier |
| Canton: | Roye |
| Insee: | 80623 |
| Postal Code: | 80500 |
| Mayor: | Brigitte Devismes[1] |
| Term: | 2020 - 2026 |
| Intercommunality: | CC Grand Roye |
| Coordinates: | 49.6306°N 2.6425°W |
| Elevation M: | 104 |
| Elevation Min M: | 82 |
| Elevation Max M: | 119 |
| Area Km2: | 12.29 |
Piennes-Onvillers is a commune in the Somme department in Hauts-de-France in northern France.
The commune is situated on the D135 and D468 crossroads, some 25miles southeast of Amiens.