| En Name: | Ust-Koksinsky District |
| Ru Name: | Усть-Коксинский район |
| Loc Name1: | Кӧк-Суу Оозы аймак |
| Loc Lang1: | Altai |
| Image View: | Jezero Akkem a masív Běluchy.jpg |
| Coordinates: | 51.95°N 142°W |
| Image Coa: | Coat of Arms of Ust-Koksinsky District (2019).png |
| Federal Subject: | Altai Republic |
| Adm Data As Of: | October 2015 |
| Adm Ctr Type: | selo |
| Adm Ctr Name: | Ust-Koksa |
| Selsoviet Type1: | Rural settlements |
| No Of Selsoviets Type1: | 9 |
| No Of Rural Localities: | 42 |
| Mun Data As Of: | March 2015 |
| Mun Formation1: | Ust-Koksinsky Municipal District |
| Mun Formation1 No Of Urban Settlements: | 0 |
| Mun Formation1 No Of Rural Settlements: | 9 |
| Area Km2: | 12960 |
| Pop 2010Census: | 17020 |
| Urban Pop 2010Census: | 0% |
| Rural Pop 2010Census: | 100% |
| Established Date: | October 19, 1923 |
| Prev Name1: | Uymonsky District |
| Prev Name1 Date: | April 10, 1933 |
| Website: | http://www.altay-ust-koksa.ru |
| Date: | June 2017 |
| Population of Ust-Koksinsky District | |
| Label1: | 2010 Census |
| Data1: | 17,020 |
| Label2: | 2002 Census |
| Data2: | 17,481 |
| Label3: | 1989 Census |
| Data3: | 16,734 |
| Label4: | 1979 Census |
| Data4: | 16,367 |
Ust-Koksinsky District (Russian: Усть-Ко́ксинский райо́н; Southern Altai: Кӧк-Суу Оозы аймак, Kök-Suu Oozı aymak) is an administrative[1] and municipal[2] district (raion), one of the ten in the Altai Republic, Russia. It is located in the west and southwest of the republic. The area of the district is 12960km2.[3] Its administrative center is the rural locality (a selo) of Ust-Koksa. As of the 2010 Census, the total population of the district was 17,020, with the population of Ust-Koksa accounting for 25.7% of that number.
The district was established on October 19, 1923 as Uymonsky District (Russian: Уймонский район)[4] within Oirot Autonomous Oblast.[5] It was given its present name on April 10, 1933.
Within the framework of administrative divisions, Ust-Koksinsky District is one of the ten in the Altai Republic. As a municipal division, the district is incorporated as Ust-Koksinsky Municipal District. Both administrative and municipal districts are divided into the same nine rural settlements, comprising forty-two rural localities. The selo of Ust-Koksa serves as the administrative center of both the administrative and municipal districts.
The district is home to two nature reserves: Katunsky State Natural Biosphere Reserve[6] and Belukha Nature Park.