Ongudaysky District (Russian: Онгуда́йский райо́н; Altay: Оҥдой аймак, Oñdoy aymak) is an administrative[1] and municipal[4] district (raion), one of the ten in the Altai Republic, Russia.

The area of the district is 11,744 square kilometers (4,534 sq mi).

[2] Its administrative center is the rural locality (a selo) of Onguday.

[3] Within the framework of administrative divisions, Ongudaysky District is one of the ten in the Altai Republic.

[4] Both administrative[1] and municipal[4] districts are divided into the same ten rural settlements, comprising thirty rural localities.