The river Tobol or Tobyl (in Russian Тобол) is an affluent on the left of the Irtych which takes its source in the Kazakh steppe . Its course is of 1591 km.

Tobol begins its way close to the Russo-Kazakh border, in Kazakh territory but not far from the Russian city of Orsk. It then bears the Kazakh name of Tobyl. It skirts the border and goes up towards north, passes by the town of Qostanay before crossing the Russo-Kazakh border to the north of the country. It passes then from the Kazakh steppe to the Siberian plain and takes again its Russian name Tobol. The river crosses the way of the Trans-Siberian railway line with Kourgan and is thrown in Irtych with Tobolsk in Fédération of Russia.