Chaetocercus is a genus of hummingbirds in the family Trochilidae.

The genus Chaetocercus was introduced in 1855 by the English zoologist George Robert Gray with the rufous-shafted woodstar as the type species.

[1][2] The name is a combination of the Ancient Greek words khaitē, meaning "hair" and kerkos, meaning "tail".

All these species, except for the rufous-shafted woodstar, were formerly placed in the genus Acestrura.

[5] In 1999 Karl-Ludwig Schuchmann remarked in the Handbook of the Birds of the World that for the species placed in Acestrura: "...no evidence in external morphology justifies treatment in a genus separate from C.