The Green-bellied Hummingbird (Amazilia viridigaster), sometimes placed in the genus Saucerottia, is a species of hummingbird in the Trochilidae family. It is found in Brazil, Colombia, Guyana, and Venezuela. The western taxa of the Andean slopes and the eastern taxa of the Tepui region are sometimes considered separate species, with the former retaining the scientific and common name, while the latter is named the Copper-tailed Hummingbird (Amazilia cupreicauda, with races duidae and laireti), also sometimes placed in the genus Saucerottia. As the variation largely is clinal, most authorities, notably SACC, consider it a single species.
Its natural habitats are subtropical or tropical dry forests, subtropical or tropical moist lowland forests, subtropical or tropical moist montanes, and heavily degraded former forest.