The Bogdashkina () is a river in the Sakha Republic (Yakutia), Russia. It has a length of and a drainage basin area of .
The river flows north of the Arctic Circle, across desolate territories of the Allaikhovsky District.
Not counting the New Siberian Islands the Bogdashkina is the northernmost sizeable river basin of Yakutia. It has its sources in a small unnamed lake of the northern end of the East Siberian Lowland. The river flows roughly northeastwards across the tundra in the uppermost section of its course. Then it flows eastwards, with its channel meandering all along. In its last stretch the Bogdashkina turns north and its mouth widens as it empties into the East Siberian Sea, roughly halfway between Khroma Bay and Gusinaya Bay. Lake Mogotoyevo, a coastal lagoon, lies to the east of the river mouth.
The main tributary of the Bogdashkina is the long Maly Bogdashkina on the left, as well as the long Bezymyanka (ÃÂõ÷ÃÂüÃÂýúð) and the long Iterbashevo (ÃÂÃÂõÃÂñðÃÂõòþ) on the right. There are many small lakes in the basin, including Shilikino lake just west of the last stretch of the Bogdashkina.
In the summer the river mouth area is a breeding place for migratory birds, including waders and the spectacled eider.