The ruby-cheeked sunbird was formally described in 1789 by the German naturalist Johann Friedrich Gmelin in his revised and expanded edition of Carl Linnaeus's Systema Naturae.

The locality was designated as Malacca on the Malay Peninsula by the American ornithologist Harry C. Oberholser in 1912.

[3][4] Gmelin based his account on the "green warbler" from the East Indies that had been described and illustrated in 1776 by the English naturalist Peter Brown.

[5] The ruby-cheeked sunbird is now the only species placed in the genus Chalcoparia that was introduced in 1850 by the German ornithologist Jean Cabanis.

[8] Eleven subspecies are recognised:[7] It is found in Bangladesh, Bhutan, Brunei, Cambodia, China, India, Indonesia, Laos, Malaysia, Myanmar, Nepal, Thailand, and Vietnam.