| Treffrin | |
| Native Name: | Trefrin |
| Commune Status: | Commune |
| Coordinates: | 48.2997°N -3.5156°W |
| Insee: | 22351 |
| Postal Code: | 22340 |
| Arrondissement: | Guingamp |
| Canton: | Rostrenen |
| Mayor: | Étienne Le Fer[1] |
| Term: | 2020 - 2026 |
| Intercommunality: | Poher Communauté |
| Elevation Min M: | 85 |
| Elevation Max M: | 174 |
| Area Km2: | 7.47 |
Treffrin (in French pronounced as /tʁɛfʁɛ̃/;) is a commune in the Côtes-d'Armor department in Brittany in northwestern France.
Inhabitants of Treffrin are called treffrinois in French.