| Lanvallay | |
| Native Name: | Lanvalae |
| Commune Status: | Commune |
| Image Coat Of Arms: | Blason ville fr Lanvallay (Côtes-d'Armor).svg |
| Coordinates: | 48.4558°N -2.0269°W |
| Insee: | 22118 |
| Postal Code: | 22100 |
| Arrondissement: | Dinan |
| Canton: | Lanvallay |
| Mayor: | Bruno Ricard[1] |
| Term: | 2020 - 2026 |
| Intercommunality: | Dinan Agglomération |
| Elevation Min M: | 7 |
| Elevation Max M: | 87 |
| Area Km2: | 14.61 |
Lanvallay (in French pronounced as /lɑ̃valɛ/;) is a commune in the Côtes-d'Armor department of Brittany in northwestern France.
Inhabitants of Lanvallay are called côtissois in French.
There is a twinning arrangement with Walkern, Hertfordshire.[2] This was initiated around the time of the 800th anniversary of the Magna Carta.