Öndörkhaan (Mongolian: Өндөрхаан; ᠥᠨᠳᠦᠷᠬᠠᠨ; sometimes Undurkhaan), is a town in Mongolia located 290 km east of Ulaanbaatar.

Öndörkhaan experiences a semi-arid climate (Köppen BSk) with long, dry, frigid winters and short, very warm summers.

Coal mining is important to the economy of the town and Chandgana Tal coalfield is located 53 km W from Öndörkhaan.

There exists a major United Nations Development Programme (UNDP) Networking and Cluster Development project stationed in Öndörkhaan specializing in the strengthen of urban, peri-urban and rural business associations and networks so as to reduce the very high unemployment rates.

The Öndörkhaan Airport (UNR/ZMUH) has one unpaved runway and was serviced by regular flights from and to Ulaanbaatar, before the paved highway was completed.