| Official Name: | Nizhny Sayantuy |
| Native Name: | Нижний Саянтуй |
| Settlement Type: | Selo |
| 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: | 51.7333°N 138°W[1] |
Nizhny Sayantuy (Russian: Нижний Саянтуй; Buriat: Доодо Саянта, Doodo Saianta) is a rural locality (a selo) in Tarbagataysky District, Republic of Buryatia, Russia. The population was 2,829 as of 2010.[2] There are 97 streets.
Nizhny Sayantuy is located 36 km north of Tarbagatay (the district's administrative centre) by road. Voznesenovka is the nearest rural locality.[3]