| Official Name: | Sayantuy |
| Native Name: | Саянтуй |
| Settlement Type: | Settlement |
| Pushpin Map: | Russia Buryatia#Russia |
| Subdivision Type: | Country |
| Subdivision Name: | Russia |
| Subdivision Name1: | Republic of Buryatia |
| Subdivision Name3: | Tarbagataysky District |
| Subdivision Type4: | Municipality |
| Utc Offset1: | +8:00 |
| Coordinates: | 51.6833°N 133°W[1] |
Sayantuy (ru|Саянтуй; bua|Саянта, Saianta) is a rural locality (a settlement) in Tarbagataysky District, Republic of Buryatia, Russia. The population was 138 as of 2010.[2] There are 9 streets.
Sayantuy is located 29 km north of Tarbagatay (the district's administrative centre) by road. Voznesenovka is the nearest rural locality.[3]