It is replaced by a near-relative, the Damara red-billed hornbill, in the arid woodlands of western Namibia.

It is usually treated as a monotypic taxon, but two additional subspecies have been proposed:[1] T. r. degens is the smallest in size, while T. r. ngamiensis has browner plumage and a more distinct tail bar.

Males also have somewhat longer bills, with the lower mandible coloured black to a variable extent.

[1] It is distinguishable from other red-billed hornbills by the combination of yellow iris and pale orbital skin (pink to greyish), and the ample blackish plumage streaking from the ear coverts to the side of the neck.

It occurs in the upper Zambezi valley of Mozambique, but is mostly absent from the eastern lowlands.