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.

A songbird is a bird belonging to the suborder Passeri of the perching birds (Passeriformes). Another name that is sometimes seen as the scientific or vernacular name is Oscines, from Latin oscen, "songbird". The Passeriformes contains 5,000 or so species found all over the world, in which the vocal organ typically is developed in such a way as to produce a diverse and elaborate bird song.