Pycnonotus was found to be polyphyletic in recent molecular phylogenetic studies and five bulbul species, including the ruby-throated bulbul, moved to Rubigula.

[2][3] Until 2008, the ruby-throated bulbul was considered as conspecific with the black-capped, black-crested, flame-throated and Bornean bulbuls,[4] but these are all now treated as distinct.

[2] There are two subspecies:[2] It is 17–20 cm long, virtually crestless, has a black head with a deep red throat, greenish-yellow back and wings, yellow underparts, and a greenish-black tail.

It builds its nest in a bush; two to four eggs are a typical clutch.

The ruby-throated bulbul feeds on fruit and insects.