Harrisoniella hopkinsi is a species of phtilopterid louse that lives on and eats the feathers of albatrosses. The species was first described by W. Eichler in 1952. There are usually fewer than half a dozen adult specimens are usually found on a single host bird, which is low compared with other species of feather lice which may number in the hundreds. They are dark brown with an elongated head, and extremely large – H. hopkinsi is one of the largest louse species, with males reaching up to 9 millimetres (0.35 in) long. They live mostly on the wing feathers, but are quite able to move if disturbed or if their host bird should die. Harrisoniella hopkinsi has been found on the feathers of the wandering albatross (Diomedea exulans) and the southern royal albatross (Diomedea epomophora).