Kosov is the name of a Hasidic dynasty founded by Rabbi Menachem Mendel Hager of Kosiv, a town in Galicia, presently in Ukraine.The present Rebbe is Grand Rabbi Shraga Hager, who lives in Borough Park, Brooklyn, where most of his Hasidim also live
The main Kosover synagogue is on 52nd St. and 11th Ave. The Kosover tish Hall is celebrated in the basement of the Satmar school in Boro Park.

The Vizhnitz dynasty is a branch of the old Kosover dynasty, but the present Kosover Rebbe is himself a scion of the Vizhnitz Dynasty.