Arsk (Tatar: Ar a / ar`ʆa/; Russian: Арск /arsk/) is a town in northern-eastern Tatarstan, Russia. It is located 65 km from Kazan, the republic's capital. Arsk is the administrative center of the Arsky District. The town stands on the banks of the Kazanka River. Arsk is also a station on the Kazan- gerce railroad. The town was founded in the 13th century by Volga Bulgarians.

The Tatar name of the town (Ar a) can be translated as Udmurt's or Udmurtian. The town was a capital of Arsk Darugha (Ar a daruğası) during the Kazan Khanate period (a darugha was a type of subdivision of Kazan Khanate). Even though the town was located in the area mostly populated by Tatars, the larger part of its population was Udmurt. It is possible that earlier population of this area was also Finnic, who later assimilated with the Tatars.

2002 population—17,211 (Tatars—83%, Russians—15%).