Wrens are a family of brown passerine birds in the predominantly New World family Troglodytidae. The family includes 88 species divided into 19 genera. Only the Eurasian wren occurs in the Old World, where, in Anglophone regions, it is commonly known simply as the "wren", as it is the originator of the name. The name wren has been applied to other, unrelated birds, particularly the New Zealand wrens (Acanthisittidae) and the Australian wrens (Maluridae).

A passerine is any bird of the order Passeriformes which includes more than half of all bird species. Sometimes known as perching birds, passerines generally have an anisodactyl arrangement of their toes, which facilitates perching.