The Buolkalakh (; , Buolkalax) is a river in Yakutia (Sakha Republic), Russia. It is a tributary of the Olenyok with a length of and a drainage basin area of .
It is a lowland river with its mouth very close to the Olenyok delta. It flows north of the Arctic Circle across a lonely, desolate tundra area devoid of settlements.
The Buolkalakh is a left tributary of the Olenyok. It has its origin in a swampy area full of lakes, just a little north of the sources of the Udya and the Bur. It flows roughly northwestwards, meandering along its course. After the confluence of the Khaastaakh it flows roughly northwards, skirting a low ridge. Finally it joins the left bank of the Olenyok river only upstream of its mouth. The confluence is a little upstream from the village of Ust-Olenyok.
The river is fed by snow and rain. It is frozen between early October and early June. The longest tributaries are the long Khaastaakh (Ã¥ððÃÂÃÂððà) and the long Molokho (ÃÂþûþàþ) from the right. The river basin is mostly in Olenyoksky District, with the upper course section of the Khaastaakh in Bulunsky District.