| Official Name: | Ust-Gryaznukha |
| Native Name: | Усть-Грязнуха |
| Settlement Type: | Selo |
| Pushpin Map: | Russia Volgograd Oblast#Russia |
| Subdivision Type: | Country |
| Subdivision Name: | Russia |
| Subdivision Name1: | Volgograd Oblast |
| Subdivision Name3: | Kamyshinsky District |
| Subdivision Type4: | Municipality |
| Utc Offset1: | +4:00 |
| Coordinates: | 50.4667°N 70°W[1] |
Ust-Gryaznukha (Russian: Усть-Грязнуха) is a rural locality (a selo) and the administrative center of Ust-Gryaznukhinskoye Rural Settlement, Kamyshinsky District, Volgograd Oblast, Russia. The population was 856 as of 2010,[2] in the 14 streets that make up the centre.[3]
Ust-Gryaznukha is located in forest steppe, on the Volga Upland, on the right bank of the Gryaznukha River, 51 km north of Kamyshin (the district's administrative centre) by road. Verkhnyaya Gryaznukha is the nearest rural locality.[4]