The chestnut-breasted coronet (Boissonneaua matthewsii) is a species of hummingbird in the "brilliants", tribe Heliantheini in subfamily Lesbiinae.

Both sexes have a short, straight, black bill, a white spot behind the eye, and a notched tail.

[5] The chestnut-breasted coronet is found from extreme southeastern Colombia south along the east slope of the Andes through Ecuador and Peru as far as Cuzco Department.

[5] The chestnut-breasted coronet is highly territorial and defends clusters of flowers from other nectar-feeding birds.

One description of chestnut-breasted coronet vocalizations is "a high, thin, liquid tip, a rapid, sweet trill, and various squeaky notes.

[5] Media related to Chestnut-breasted Coronet (Boissonneaua matthewsii) at Wikimedia Commons