Zhaksy-Zhalgyztau (Kazakh: Жақсы Жалғызтау; Russian: Жаксы-Жалгызтау), is a lake in Aiyrtau District, North Kazakhstan Region, and Sandyktau District, Akmola Region, Kazakhstan.

[1] Zhaksy-Zhalgyztau village is located by the northeastern and Priozyornoye by the southern lakeshore.

The shape of the lake is irregular, with two wide bays in the north separated by a broad landspit.

729 meters (2,392 ft) high Zhaksy-Zhalgyztau mountain rises above the southwestern lakeshore.

Among the fishes living in the lake perch, common roach, bream, pike, zander, Eurasian carp, ide and catfish deserve mention.