The rainbow lorikeet (Trichoglossus moluccanus) is a species of parrot found in Australia. It is common along the eastern seaboard, from northern Queensland to South Australia. Its habitat is rainforest, coastal bush and woodland areas. Six taxa traditionally listed as subspecies of the rainbow lorikeet are now treated as separate species (see Taxonomy).

Rainbow lorikeets have been introduced to Perth, Western Australia; Tasmania; Auckland, New Zealand; and Hong Kong.

The rainbow lorikeet was formally listed in 1788 by the German naturalist Johann Friedrich Gmelin under the binomial name Psittacus moluccanus. Gmelin cited the French polymath Georges-Louis Leclerc, Comte de Buffon who in 1779 had published a description of "La Perruche à Face Bleu" in his Histoire Naturelle des Oiseaux. The species was illustrated as the "Peluche des Moluques" and as the "Perruche d'Amboine". Gmelin was misled and coined the specific epithet moluccanus as he believed the specimens had come from the Moluccas. The type locality was changed to Botany Bay in Australia by Gregory Mathews in 1916. The rainbow lorikeet is now placed in the genus Trichoglossus that was introduced in 1826 by the English naturalist James Francis Stephens.

Two subspecies are recognised:

The rainbow lorikeet has often included the red-collared lorikeet (T. rubritorquis) as a subspecies, but today most major authorities consider it separate. Additionally, a review in 1997 led to the recommendation of splitting off some of the most distinctive taxa from the Lesser Sundas as separate species, these being the scarlet-breasted lorikeet (T. forsteni), the marigold lorikeet (T. capistratus) and the Flores lorikeet (T. weberi). This is increasingly followed by major authorities. In 2019 The rainbow lorikeet in Australia was split into three: rainbow, coconut (T. haematodus) and red-collared lorikeets (T. rubritorquis).

Three syntypes of Trichoglossus novaehollandiae septentrionalis Robinson (Bull. Liverpool Mus., 2, 1900, p.115) are held in the vertebrate zoology collection of National Museums Liverpool at World Museum, with accession numbers NML-VZ 23.7.1900.4, NML-VZ 23.7.1900.4a, and NML-VZ 23.7.1900.4b. The specimens were collected in Cooktown, Queensland, Australia by E. Olive. The specimens came to the Liverpool national collection via purchase from H. C. Robinson.

The rainbow lorikeet is a medium-sized parrot, with the length ranging from 25 to 30 cm (9.8 to 11.8 in) including the tail, and the weight varies from 75 to 157 g (2.6–5.5 oz). The plumage of the nominate race, as with all subspecies, is very bright and colorful. The head is deep blue with a greenish-yellow nuchal collar, and the rest of the upper parts (wings, back and tail) are green. The chest is orange/yellow. The belly is deep blue, and the thighs and rump are green. In flight a yellow wing-bar contrasts clearly with the red underwing coverts. There is little to visually distinguish between the sexes.

Juveniles have a black beak, which gradually brightens to orange in the adults.