Halcyoninae or tree kingfishers and wood kingfishers, is a subfamily of kingfishers. The family appears to have arisen in Indochina and Maritime Southeast Asia and then spread to many areas around the world. Tree kingfishers are widespread through Asia and Australasia, but also appear in Africa and the islands of the Pacific and Indian Oceans, using a range of habitats from tropical rainforest to open woodlands.

The tree kingfishers are short-tailed, large-headed, compact birds with long, pointed bills. Like other Coraciiformes, they are brightly colored. Most are monogamous and territorial, nesting in holes in trees or termite nests. Both parents incubate the eggs and feed the chicks. Although some tree kingfishers frequent wetlands, none are specialist fish-eaters. Most species dive onto prey from a perch, mainly taking slow-moving invertebrates or small vertebrates.