The amethyst woodstar (Calliphlox amethystina) is a species of hummingbird in the family Trochilidae. It is found in most of central, and eastern South America proper, in Argentina, Bolivia, Brazil, Colombia, Ecuador, French Guiana, Guyana, Suriname-(the Guianas), Paraguay, Peru, and Venezuela. The bird's range surrounds the Amazon countries into the Andes foothills and higher elevations of upstream river systems, but is not along the Amazon River proper in the central Amazon Basin, or the central upper Basin; it is in Brazil at the river's outlet, and upstream for about 500 km.
The amethyst woodstar's natural habitats are subtropical or tropical moist lowland forests and subtropical or tropical moist montane forests. At 7.5 cm (3 in) and under 3 grams in weight, this is one of the smallest birds in existence.