Hair of the Dog is the sixth studio album by the Scottish hard rock band Nazareth, released on 3 April 1975. The album was recorded at Escape Studios, Kent, with additional recording and mixing at AIR Studios, London, and is the group's best known and highest selling release, with over two million copies sold worldwide.

Hard rock or heavy rock is a heavier subgenre of rock music typified by aggressive vocals and distorted electric guitars. Hard rock began in the mid-1960s with the garage, psychedelic and blues rock movements. Some of the earliest hard rock music was produced by the Kinks, the Who, the Rolling Stones, Cream, Vanilla Fudge, and the Jimi Hendrix Experience. In the late 1960s, bands such as Blue Cheer, the Jeff Beck Group, Iron Butterfly, Led Zeppelin, Golden Earring, Steppenwolf, and Deep Purple also produced hard rock.