Osinsky District (Russian: Оси́нский райо́н; Buryat: Оһын аймаг, Ohyn aimag) is an administrative district of Ust-Orda Buryat Okrug of Irkutsk Oblast, Russia, one of the thirty-three in the oblast.

[6] It is located in the south of the oblast.

The area of the district is 4,400 square kilometers (1,700 sq mi).

[3] Its administrative center is the rural locality (a selo) of Osa.

[10] The population of Osa accounts for 22.1% of the district's total population.