The sun conure (Aratinga solstitialis), also known as the sun parakeet, is a medium-sized, vibrantly colored parrot native to northeastern South America. The adult male and female are similar in appearance, with black beaks, predominantly golden-yellow plumage, orange-flushed underparts and face, and green and blue-tipped wings and tails. Sun conures are very social birds, typically living in flocks. They form monogamous pairs for reproduction, and nest in palm cavities in the tropics. Sun conures mainly feed on fruits, flowers, berries, blossoms, seeds, nuts, and insects. Conures are commonly bred and kept in aviculture and may live up to 30 years. This species is currently threatened by loss of habitat and trapping for plumage or the pet trade. Sun conures are now listed as endangered by the International Union for Conservation of Nature.

The sun conure was one of the many species originally described by Carl Linnaeus in his landmark 1758 10th edition of Systema Naturae. As Linnaeus did with many of the parrots he described, he placed this species in the genus Psittacus, but it has since been moved to the widely accepted Aratinga, which contains a number of similar New World species, while Psittacus is now restricted to the type species, the grey parrot and the closely related Timneh parrot. The specific epithet solstitialis is derived from the Latin for 'of the summer solstice', hence 'sunny', and refers to its golden plumage. The two widely used common names are "sun conure", used in aviculture, by the World Parrot Trust and some authorities such as Thomas Arndt and Joseph Forshaw, and "sun parakeet" as used by the American Ornithologists' Union and widely by official birdlists, field guides, and birders. However, this is the only species of "conure" that is regularly referred to as such in ornithological circles; most others are called "parakeets" by authorities.

The sun conure is monotypic, but the Aratinga solstitialis complex includes three additional species from Brazil: jandaya parakeet, golden-capped parakeet, and sulphur-breasted parakeet. These have all been considered subspecies of the sun conure, but most recent authorities maintain their status as separate species. Alternatively, the sun conure and the sulphur-breasted parakeet have been suggested to represent one species, while the jandaya parakeet and golden-capped parakeet represent a second. Of these, the sulphur-breasted parakeet only received widespread recognition in 2005, having gone unnoticed at least partially due to its resemblance to certain preadult plumages of the sun conure. The sun, jandaya, and golden-capped parakeets all can interbreed in captivity (the sulphur-breasted also likely will interbreed with these). In the wild, hybrids between the jandaya parakeet and golden-capped parakeet have been reported in their limited area of contact, but most such individuals could be subadults (which easily could be confused with hybrids). As far as known, the remaining taxa are entirely allopatric, although the sun conure and the sulphur-breasted parakeet possibly come into contact in the southern Guianas, where some doubts exist over their exact identity.

The sun conure is the closest living relative of the extinct Carolina parakeet and as such, its genes have been sequenced for comparative purposes, in relation to studying the genome of the latter species. The two species last shared a common ancestor about 3 million years ago, coinciding with the closure of the Isthmus of Panama, which allowed easier dispersal of species between North and South America.

On average, sun conures weigh around 110 g (4 oz) and are around 30 cm (12 in) long. The sexes are similar in plumage, although hens may be lighter and slenderer in body, having a shorter tail, with a smaller, rounder head and a smaller beak. Adults have a rich yellow crown, nape, mantle, lesser wing coverts, tips of the greater wing coverts, chest, and underwing coverts. The face and belly are orange with red around the ears. The base of the greater wing coverts, tertials, and base of the primaries are green, while the secondaries, tips of the primaries, and most of the primary coverts are dark blue. The tail is olive-green with a blue tip. From below, all the flight feathers are dark greyish. The bill is black. The legs and the bare eye ring are grey, but the latter often fades to white in captivity (so using amount of grey or white in the eye ring for determining "purity" of an individual can be misleading). It is easily confused with the closely related jandaya parakeet and sulphur-breasted parakeet, but the former has entirely green wing coverts, mantle, and vent, while the latter has green mottling to the mantle and less orange to the underparts. The sun conure is also superficially similar to the pale-billed golden parakeet.

Juvenile sun conures display a predominantly green plumage and resemble similarly aged sulphur-breasted parakeets. The distinctive yellow, orange, and reddish colouration on the back, abdomen, and head is attained with maturity.

Sun conures live in a relatively small region of northeastern South America – the north Brazilian state of Roraima, southern Guyana, extreme southern Suriname, and southern French Guiana. They also occur as vagrants to coastal French Guiana. Their status in Venezuela is unclear, but recent sightings from the southeast near Santa Elena de Uairén have been reported. They may occur in Amapá or far northern Pará (regions where the avifauna generally is very poorly documented), but this remains to be confirmed. Populations found along the Amazon River in Brazil are now known to belong to the sulphur-breasted parakeet.

Sun conures are mostly found in tropical habitats, but their exact ecological requirements remain relatively poorly known. They are widely reported as occurring within dry savanna woodlands and coastal forests, but recent sightings suggest they mainly occur at altitudes less than 1,200 m (3,900 ft), at the edge of humid forests growing in foothills in the Guiana Shield, and cross more open savannah habitats only when traveling between patches of forest. Sun conures have been seen in shrublands along the Amazon riverbank, as well as forested valleys and coastal, seasonally flooded forests. These conures usually inhabit fruiting trees and palm groves.