| Guichen | |
| Native Name: | (Gallo) |
| Commune Status: | Commune |
| Image Coat Of Arms: | Blason ville fr Guichen (Ille-et-Vilaine).svg |
| Coordinates: | 47.9681°N -1.7939°W |
| Insee: | 35126 |
| Postal Code: | 35580 |
| Arrondissement: | Redon |
| Canton: | Guichen |
| Mayor: | Dominique Delamarre[1] |
| Term: | 2020 - 2026 |
| Intercommunality: | Vallons de Haute-Bretagne |
| Elevation Min M: | 7 |
| Elevation Max M: | 107 |
| Area Km2: | 42.99 |
Guichen (pronounced as /fr/; ; Gallo: Gischen) is a commune in the Ille-et-Vilaine department in Brittany in northwestern France.
Inhabitants of Guichen are called Guichenais in French.