The Grebensky Cossacks or Grebentsy was a group of Cossacks formed in the 16th century from Don Cossacks who left the Don area and settled in the northern foothills of the Caucasus. The Greben Cossacks are part of the Terek Cossacks. They were influenced by Chechen and Nogai culture and most were bilingual in the Russian language and the Nogai language.

According to the article on Grebentsy in ЭСБЕ (1893), whose author is — a writer V. E. Rudakov [ru] — referring to some historians, who, in turn, allegedly relied on materials from «Book to the Big Drawing [ru]» and the legend of the Grebensky icon^{[lower-alpha 1]}, claimed that Grebensky Cossacks descended from the Don Cossacks who settled in the Caucasus, whose community originally lived in the interfluve Seversky Donets and Kalitva near a hill called the Grebensky mountains, hence the name of these Cossacks — Grebensky.^[1]