| Official Name: | Ostrog |
| Native Name: | Острог |
| Settlement Type: | Selo |
| Pushpin Map: | Russia Buryatia#Russia |
| Subdivision Type: | Country |
| Subdivision Name: | Russia |
| Subdivision Name1: | Republic of Buryatia |
| Subdivision Name3: | Pribaykalsky District |
| Subdivision Type4: | Municipality |
| Utc Offset1: | +8:00 |
| Coordinates: | 52.15°N 135°W[1] |
Ostrog (ru|Острог) is a rural locality (a selo) in Pribaykalsky District, Republic of Buryatia, Russia. The population was 100 as of 2010.[2] There are 3 streets.
Ostrog is located 13 km southwest of Turuntayevo (the district's administrative centre) by road. Koma is the nearest rural locality.[3]