The Qarqarçay () or Karkar () is a river located in Azerbaijan, in the drainage basin of the Kura. Parts of the river flow through Nagorno Karabakh. Its length is , and the area of the basin . The river begins on the Karabakh Plateau at an altitude of and is formed by the confluence of the rivers Zarysly and Khalfali. The main tributaries are the Ballyja, Badara and Daghdaghan. The Qarqar is fed by rain, snow and underground waters.
The Askeran fortress is situated on the banks of the Qarqar.
Qarqarçay, romanized as Gargarchay, consists of the name Gargar and the Turkic suffix -chay (), meaning "river". German scientist Heinrich Hübschmann explains that Karkar () is etymologized from Armenian â meaning âÂÂheap of stonesâÂÂ.