The frogmouths are a group of nocturnal birds related to owlet-nightjars, swifts, and hummingbirds. Species in the group are distributed in the Indomalayan and Australasian realms.

They are named for their large flattened hooked bill and huge frog-like gape, which they use to capture insects. The three Podargus species are large frogmouths restricted to Australia and New Guinea, that have massive flat broad bills. They are known to take larger prey such as small vertebrates (frogs, mice, etc.), which are sometimes beaten against a stone before swallowing. The ten Batrachostomus frogmouths are found in tropical Asia. They have smaller, more rounded bills and are predominantly insectivorous. Both Podargus and Batrachostomus have bristles around the base of the bill, and Batrachostomus has other, longer bristles which may exist to protect the eyes from insect prey.

Their flight is weak. They rest horizontally on branches during the day, camouflaged by their cryptic plumage. Through convergent evolution as night hunters, they resemble owls, with large front-facing eyes.

Up to three white eggs are laid in the fork of a branch, and are incubated by the female at night and the male in the day.

DNA-DNA hybridisation studies had suggested that the two frogmouth groups may not be as closely related as previously thought, and that the Asian species may be separable as a new family, the Batrachostomidae. Although frogmouths were formerly included in the order Caprimulgiformes, a 2019 study estimated the divergence between Podargus and Batrachostomus to between 30 and 50 mya and forming a clade well separated from the nightjars and being a sister group of the swifts, hummingbirds, and owlet-nightjars. The name Podargiformes proposed in 1918 by Gregory Mathews was reinstated for the clade.