| Official Name: | Buy |
| Native Name: | Буй |
| Settlement Type: | Selo |
| Pushpin Map: | Russia Buryatia#Russia |
| Subdivision Type: | Country |
| Subdivision Name: | Russia |
| Subdivision Name1: | Republic of Buryatia |
| Subdivision Name3: | Bichursky District |
| Subdivision Type4: | Municipality |
| Utc Offset1: | +8:00 |
| Coordinates: | 50.6333°N 165°W[1] |
Buy (Russian: Буй) is a rural locality (a selo) in Bichursky District, Republic of Buryatia, Russia. The population was 659 as of 2010.[2] There are 6 streets.
Buy is located 34 km east of Bichura (the district's administrative centre) by road. Sloboda is the nearest rural locality.[3]