Isilkul (Russian: Исильку́ль; Kazakh: Есілкөл, romanized: Esılköl) is a town in Omsk Oblast, Russia, located 120 kilometers (75 mi) west of Omsk, the administrative center of the oblast.

Within the framework of administrative divisions, Isilkul serves as the administrative center of Isilkulsky District, even though it is not a part of it.

[1] As an administrative division, it is incorporated separately as the town of oblast significance of Isilkul—an administrative unit with the status equal to that of the districts.

[1] As a municipal division, the town of oblast significance of Isilkul is incorporated within Isilkusky Municipal District as Isilkul Urban Settlement.

[3] The town is a transfer point on the southern branch of the Trans-Siberian Railway between the Western Siberian and Sverdlovsk railroads.