Lyall's wren or the Stephens Island wren was a small, flightless passerine belonging to the family Acanthisittidae, the New Zealand wrens. Now extinct, it was once found throughout New Zealand, but when it came to the attention of scientists in 1894, its last refuge was Stephens Island in Cook Strait. Often claimed to be a species driven extinct by a single creature, the wren in fact fell victim to the island's numerous feral cats. The wren was described almost simultaneously by both Walter Rothschild and Walter Buller. It became extinct shortly after.

The New Zealand wrens are a family (Acanthisittidae) of tiny passerines endemic to New Zealand. They were represented by seven Holocene species in four or five genera, although only two species in two genera survive today. They are understood to form a distinct lineage within the passerines, but authorities differ on their assignment to the oscines or suboscines. More recent studies suggest that they form a third, most ancient, suborder Acanthisitti and have no living close relatives at all. They are called "wrens" due to similarities in appearance and behaviour to the true wrens (Troglodytidae) but are not members of that family.