Rainbow Bee-eaters are brilliantly coloured birds that grow to be 23–28 cm (9.1–11.0 in) in length, including the elongated tail feathers, and weighing 20–33 g
The upper back and wings are green in colour, and the lower back and under-tail coverts are bright blue. The undersides of the wings and primary flight feathers are rufous to copper with green edges and tipped with black, and the tail is black to deep violet The Rainbow Bee-eater's two central tail feathers are longer than the other tail feathers, and are longer in the male Rainbow Bee-eaters than in the females.
The crown of the head, the stomach and breast, and the throat are pale yellow-orange in color, and it has a black crescent-shaped gorget and a black stripe, edged with blue, extending through its bright red eye. They have small, syndactylous feet (i.e., with toes partly united). The juvenile has a greener crown, lacks throat bands and tail streamers.