The Green-rumped Parrotlet, Forpus passerinus, is a small parrot. It is a resident breeding bird in tropical South America, from Caribbean regions of Colombia, Venezuela and Trinidad south and east to the Guianas and Brazil, on the downstream Amazon River. It has been introduced in Jamaica, Curaçao, Barbados and Tobago, and was not recorded on Trinidad prior to 1916.

Its habitat is open forest and scrub. The female lays five to seven white eggs in a hole in a termite nest, tree cavity, or even hollow pipe, and incubates the clutch for 18 days to hatching, with about another five weeks to fledging.

The Green-rumped Parrotlet is about 12 cm (4.8 in) long and weighs 23 g and is the smallest parrot found in the Americas. It is mainly bright green with a short tail and pinkish bill. The male has a brilliant blue wing patch, and females sometimes have some yellow on the head. The subspecies F. p. viridissimus of Venezuela, Trinidad and Tobago is darker green than the nominate F. p. passerinus, and the males have more strongly blue-tinged wings.

Green-rumped Parrotlets make light, twittering calls. They eat seeds including those of grasses. They are very gregarious and roost communally; large numbers can be seen at the roost sites at dawn and dusk.

This is a widespread and common species which has benefited from deforestation.