The red grouse is a medium-sized bird of the grouse family which is found in heather moorland in Great Britain and Ireland. It is usually classified as a subspecies of the willow ptarmigan but is sometimes considered to be a separate species, Lagopus scoticus. It is also known as the moorcock, moorfowl or moorbird. Lagopus is derived from Ancient Greek lagos (λαγος), meaning "hare", + pous (πους), "foot", in reference to the feathered feet and toes typical of this cold-adapted genus, and scoticus is "of Scotland".

Grouse are a group of birds from the order Galliformes, in the family Phasianidae. Grouse are presently assigned to the tribe Tetraonini, a classification supported by mitochondrial DNA sequence studies, and applied by the American Ornithologists' Union, ITIS, International Ornithological Congress, and others.