| Official Name: | Tuldun |
| Native Name: | Тулдун |
| Native Name Lang: | ru |
| Settlement Type: | Settlement |
| Pushpin Map: | Russia Buryatia#Russia |
| Subdivision Type: | Country |
| Subdivision Name: | Russia |
| Subdivision Type1: | Region |
| Subdivision Name1: | Republic of Buryatia |
| Subdivision Type2: | County |
| Subdivision Type3: | District |
| Subdivision Name3: | Yeravninsky District |
| Subdivision Type4: | Municipality |
| Utc Offset1: | +8:00 |
| Coordinates: | 52.6833°N 145°W[1] |
Tuldun (Russian: Тулдун) is a rural locality (a settlement) and the administrative centre of Tuldunskoye Rural Settlement, Yeravninsky District, Republic of Buryatia, Russia. The population was 471 as of 2017.[2] There are 13 streets.
Tuldun is located 22 km north of Sosnovo-Ozerskoye (the district's administrative centre) by road, Shiringa is the nearest rural locality,[3] near the Maly Yeravna lake, part of the Yeravna-Khorga Lake System.[4]