| En Name: | Ongudaysky District |
| Ru Name: | Онгудайский район |
| Loc Name1: | Оҥдой аймак |
| Loc Lang1: | Altay |
| Image View: | Ursul valley in Altay Rep Ongudaisky distr.JPG |
| Coordinates: | 50.75°N 93°W |
| Image Coa: | Coat of Arms of Ongudaysky District.svg |
| Federal Subject: | Altai Republic |
| Adm Data As Of: | December 2014 |
| Adm Ctr Type: | selo |
| Adm Ctr Name: | Onguday |
| Selsoviet Type1: | Rural settlements |
| No Of Selsoviets Type1: | 10 |
| No Of Rural Localities: | 30 |
| Mun Data As Of: | December 2014 |
| Mun Formation1: | Ongudaysky Municipal District |
| Mun Formation1 No Of Urban Settlements: | 0 |
| Mun Formation1 No Of Rural Settlements: | 10 |
| Area Km2: | 11744 |
| Area Km2 Ref: | [1] |
| Pop 2010Census: | 15046 |
| Urban Pop 2010Census: | 0% |
| Rural Pop 2010Census: | 100% |
| Website: | http://www.ongudai-ra.ru |
| Date: | December 2012 |
| Population of Ongudaysky District | |
| Label1: | 2010 Census |
| Data1: | 15,046 |
| Label2: | 2002 Census |
| Data2: | 15,642 |
| Label3: | 1989 Census |
| Data3: | 16,417 |
| Label4: | 1979 Census |
| Data4: | 14,964 |
Ongudaysky District (Russian: Онгуда́йский райо́н; Southern Altai: Оҥдой аймак, Oñdoy aymak) is an administrative[2] and municipal[3] district (raion), one of the ten in the Altai Republic, Russia. It is located in the center of the republic. The area of the district is 11744km2.[1] Its administrative center is the rural locality (a selo) of Onguday. As of the 2010 Census, the total population of the district was 15,046, with the population of Onguday accounting for 37.6% of that number.
Within the framework of administrative divisions, Ongudaysky District is one of the ten in the Altai Republic. As a municipal division, the district is incorporated as Ongudaysky Municipal District. Both administrative and municipal districts are divided into the same ten rural settlements, comprising thirty rural localities. The selo of Onguday serves as the administrative center of both the administrative and municipal district.