Altybaysor (Kazakh: Алтыбайсор) is a salt lake in the Aksu City Administration, Pavlodar Region, Kazakhstan.

[1] The lake lies 60 kilometers (37 mi) to the SSW of Aksu city.

The area surrounding the lake is used for livestock grazing.

[2][3] Altybaysor is an endorheic lake of the northern end of the Kazakh Uplands at an elevation of 110 meters (360 ft).

The Irtysh flows 50 kilometers (31 mi) to the east of the eastern shores of the lake.