They are found in southeast Asia and the smallest members of Falconiformes, averaging about 15 cm (5.9 in) in length and 35 g (1.2 oz) in weight.

The first description by a European ornithologist of a falconet from this group was published by George Edwards in 1750, as "the little black and orange colour'd Indian hawk".

[2] In 1758 Carl Linnaeus used the illustration and description by Edwards to formally describe the species under the binomial name Falco cærulescens[3][4] In 1760 the French naturalist Mathurin Jacques Brisson also used Edwards' publication to describe le Faucon de Bengale.

Sharpe coined the name Microhierax in 1874, from the Greek μικρός ἱεραξ meaning "tiny hawk".

He lists Horsfield's specimen "Falco cærulescens" as being actually M. fringillarius, making the latter the type of the genus.