The first formal description of the little kingfisher was by the Dutch zoologist Coenraad Jacob Temminck in 1836 under the current binomial name Ceyx pusilla.

[3][4] The generic name Ceyx (/ˈsiːɪks/) derives from Ancient Greek: Κήϋξ, romanized: Kēüx, a mythological seabird that was drowned at sea and then found washed ashore by his wife Alcyone, after which both were metamorphosed into kingfishers.

[7] Subspecies C. p. halli is found in coastal north-eastern Queensland from Endeavour River to Keppel Bay; it has small blue patches extending into the sides of the breast.

[2] The little kingfisher is 11.5 to 13 cm (4.5 to 5.1 in) long with a glossy, deep-blue back and head, and a snowy white breast.

[7] The little kingfisher will make a small burrow on the bank of a river during the mating season (October to March in Queensland; February in Northern Territory; and January to April in Papua New Guinea).