The Plain-bellied Emerald (Amazilia leucogaster) is a species of hummingbird in the Trochilidae family. It is found from north-eastern Venezuela, through the Guianas, to around São Luís in Brazil. Smaller disjunct population are found in north-eastern Brazil as far south as Bahia. It occurs in a wide range of semi-open habitats, primarily in coastal regions. It is generally fairly common, and therefore considered to be of least concern by BirdLife International and consequently the IUCN. The flanks and upperparts are green, often tinged golden on the lower back and rump, while the underparts are white. The central rectrices are golden, while the outer rectrices are dark blue with narrow whitish tips. The slightly decurved bill is black with a flesh-coloured base to the lower mandible.