nglish naturalist George Edwards included an illustration and a description of an Asian koel in the second volume of his A Natural History of Uncommon Birds book. He used the English name "The Brown and Spotted Indian Cuckow". Edwards based his hand-coloured etching on a specimen from Bengal that belonged to the London silk-pattern designer and naturalist Joseph Dandridge. When in 1758 the Swedish naturalist Carl Linnaeus updated his Systema Naturae for the tenth edition, he placed the Asian koel with the other cuckoos in the genus Cuculus. Linnaeus included a brief description, coined the binomial name Cuculus scolopaceus and cited Edwards' work. The Asian koel is now placed in the genus Eudynamys that was introduced in 1827 by the English naturalists Nicholas Vigors and Thomas Horsfield. The genus name Eudynamys combines the Ancient Greek eu meaning "fine" with dunamis meaning "power" or "strength". The specific epithet scolopaceus is Modern Latin meaning "snipe-like" from Latin scolopax meaning "snipe" or "woodcock".

The species has variations within its wide range with several island populations and a number of taxonomic variations have been suggested. The black-billed koel (E. melanorhynchus) of the Sulawesi region and the Pacific koel of Australasia are sometimes considered conspecific with the Asian koel in which case the "combined" species is known as the common koel. Due to differences in plumage, colour of bill and voice, the three are increasingly treated as separate species. Alternatively, only the black-billed koel has been considered as a separate species, or the Asian koel has included all subspecies otherwise included in the Pacific koel, except for the subspecies breeding in Australia, which then has the name Australian koel (E. cyanocephalus). The Asian koel has several geographic forms that have well marked plumage differences or have been geographically isolated with little gene flow. The following is a list of named subspecies with their distribu