The wrens (Troglodytidae) are 86 species of passerine birds mainly occuring in New World. Only one species 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 family name Troglodytidae is derived from troglodyte, which means "cave-dweller", and the wrens get their scientific name from the tendency of some species to forage in dark crevices.

Wrens are mainly small and inconspicuous, except for their loud and often complex songs. These birds have short wings and they cannot see at night. Several species often hold their tails upright and sleep on the ground. Wrens are insectivorous, eating insects and spiders but they will also eat fish, small rodents and lizards.

Wrens are small birds, among the smallest in the New World. They range in size from the White-bellied Wren, which averages under 10 centimetres and 9 grams, to the Giant Wren, which averages about 22 cm and 50 g. The dominating colours of their plumage are drab, composed of grey, brown, black and white, and most species show some barring, especially to tail and/or wings. One particularly distinguishing characteristic of the family, absent in most all other songbirds, is barring on the retrices.

The various species occur in a wide range of habitats, ranging from dry, sparsely wooded country to rainforest. The vast majority are found at low levels, but some members of the genus Campylorhynchus and both members of the genus Odontorchilus are commonly found at canopy height. A few species, notably the Winter Wren and the House Wren, are often associated with humans.