| Roisan | |
| Official Name: | Comune di Roisan Commune de Roisan |
| Native Name: | Rèizàn |
| Coordinates: | 45.7833°N 26°W |
| Province: | none |
| Frazioni: | Baravex, Blavy, Careybloz, Chambrette, Champapon, Champvillair Dessous, Champvillair Dessus, Chaumé, Fontillon, Clavallaz, Closellinaz, Crétaz, Gorrey, Ladret, Les Adrets, Martinet (chef-lieu), Massinod, Moulin, Preil, Rhins, Pointier, Salé, Champ de Bau, Château, Chaviller, Chez Collin, Creusévy, Zatély |
| Mayor: | Roisan-Stemma.png |
| Area Total Km2: | 14 |
| Population Footnotes: | [1] |
| Population Total: | 1001 |
| Population As Of: | 31 December 2022 |
| Population Demonym: | Roisaëins |
| Elevation M: | 866 |
| Saint: | Saint Victor de Soleure |
| Day: | 30 September |
| Postal Code: | 11100 |
| Area Code: | 0165 |
| Istat: | 7057 |
Roisan (pronounced as /fr/; Valdôtain: Rèizàn) is a town and comune in the Aosta Valley region of north-western Italy. It is located on the left shore of the Buthier river, in the lower Valpelline.