The lilac-breasted roller (Coracias caudatus) is an African bird of the roller family, Coraciidae. It is widely distributed in Southern and Eastern Africa, and is a vagrant to the southern Arabian Peninsula. It prefers open woodland and savanna, and it is for the most part absent from treeless places. Usually found alone or in pairs, it perches at the tops of trees, poles or other high vantage points from where it can spot insects, amphibians and small birds moving about on the ground. Nesting takes place in a natural hole in a tree where a clutch of 2–4 eggs are laid, and incubated by both parents, who are extremely aggressive in defence of their nest, taking on raptors and other birds. During the breeding season the male will rise to a fair height (69 to 144 metres), descending in swoops and dives, while uttering harsh, discordant cries. The sexes do not differ in coloration, and juveniles lack the long tail streamers of adults. This species is unofficially considered the national bird of Kenya. Alternative names for the lilac-breasted roller include the fork-tailed roller, lilac-throated roller (also used for a subspecies of purple roller) and Mosilikatze's roller.

The lilac-breasted roller was formally described by the Swedish naturalist Carl Linnaeus in 1766 in the twelfth edition of his Systema Naturae under the binomial name Coracias caudata. Linnaeus based his description on "Le Rollier d'Angola" that had been described and illustrated in 1760 by the French zoologist Mathurin Jacques Brisson. The specific epithet caudatus is Latin meaning "tailed".

The lilac-breasted roller is one of nine species in genus Coracias, a group native to the open woodlands of western Eurasia and Africa.

The phylogenetic relationships among the Coracias species are shown below, from the molecular study by Johansson et al. (2018)

Two subspecies are recognized:

Though not parapatric (their breeding ranges do not meet) there is no evidence of behavioural or ecological differences that would support C. c. lorti as a separate species.

In the field, these robust, large-headed birds are often perched alone on a tree in a grassy clearing, and are almost unmistakable with their colourful plumage tones. The lilac throat of the nominate subspecies C. c. caudatus deepens into a darker lilac breast. The crown to mantle is olive, and the cheeks and ear coverts a lilac-rufous. In subspecies C. c. lorti however, the crown to mantle is greenish blue instead of olive, and the breast azure. The throat is lilac, and some lilac-throated rollers have a lilac patch or rufous-brown tinges on the lower abdomen. Both subspecies have long, black outermost tail streamers that are absent in juveniles. Lilac-breasted rollers are not sexually dimorphic though males may be slightly larger than females. Juveniles, immatures and adults have the largest alula feather dark blue, but the primary coverts and rest of the alula azure. The proximal half of the remiges are also a brilliant azure, and the distal half black on the inner web, and dark purple blue on the outer webs. Juveniles have the throat and breast rufous-tawny with broad diffuse buffy-white streaks with mauve margins on some feathers. Immatures have the breast buffy with occasional lilac feathers and diffuse pale streaking.

The average mass is 104 grams, and length ranges from 36 to 38 centimeters (inclusive of the tail streamer of 8 to 9 cm). These acrobatic fliers have an average wingspan range of 50 to 58 cm. Unique to rollers (family Coraciidae) are syndactyl feet, in which the second and third digits are fused.