The blue-crowned trogon is a species of bird in the family Trogonidae, the quetzals and trogons. It is found in Brazil, Argentina, Bolivia, Colombia, Ecuador, Paraguay, and Peru. As with all trogons, this species is sexually dimorphic. The male has a blue head with an orange orbital ring, a red belly with a narrow white breastband and a green back. The female differs in having a grey head, a grey back and a broken white eye-ring.

The trogons and quetzals are birds in the order Trogoniformes which contains only one family, the Trogonidae. The family Trogonidae contains 46 species in seven genera. The fossil record of the trogons dates back 49 million years to the Early Eocene. They might constitute a member of the basal radiation of the order Coraciiformes and order Passeriformes or be closely related to mousebirds and owls. The word trogon is Greek for "nibbling" and refers to the fact that these birds gnaw holes in trees to make their nests.