| Official Name: | Tugnuy |
| Native Name: | Тугнуй |
| Settlement Type: | Selo |
| Pushpin Map: | Russia Buryatia#Russia |
| Subdivision Type: | Country |
| Subdivision Name: | Russia |
| Subdivision Name1: | Republic of Buryatia |
| Subdivision Name3: | Mukhorshibirsky District |
| Subdivision Type4: | Municipality |
| Utc Offset1: | +8:00 |
| Coordinates: | 51.2°N 114°W[1] |
Tugnuy (Russian: Тугнуй; Buriat: Тγгнэ, Tügne) is a rural locality (a selo) in Mukhorshibirsky District, Republic of Buryatia, Russia. The population was 740 as of 2010.[2] There are 12 streets.
Tugnuy is located 40 km northeast of Mukhorshibir (the district's administrative centre) by road. Bom is the nearest rural locality.[3]