The Caucasian Black Grouse (Tetrao mlokosiewiczi) is a large bird in the grouse family. It is closely related to the Eurasian Black Grouse (T. tetrix). It occurs in extreme southwestern Europe and adjacent regions. The scientific name of this bird commemorates the Polish naturalist Ludwik Mlokosiewicz.

As with many gamebirds, the cock (male) is larger than the hen (female), measuring 50-55 cm compared to her length of 37-42 cm. The cock is very distinctive, with all-black plumage, apart from red eyebrows, and a long, deeply forked tail. The female Caucasian Black Grouse is grey with dark barring, and has a cackling call.

The Caucasian Black Grouse is a sedentary species, breeding in the Caucasus Mountains and northeast Turkey on open slopes with low Rhododendron or other scrubs. These bird have a group display or lek in early spring. Unlike the male Eurasian Black Grouse, the Caucasian Black Grouse display is almost mute, but a thin whistling is produced by the cock's wings. The hen lays up to 10 eggs in a ground scrape and takes all responsibility for nesting and caring for the chicks, as is typical with gamebirds.

This is perhaps the least-known of all grouse in the world, and it was formerly classified as Data Deficient by the IUCN. Recent research shows that it is declining to some extent, and it is consequently listed as a Near Threatened species in 2008.