Its natural habitat is subtropical or tropical moist montane forests from 1600 to 2500 m.[2] The red-capped forest warbler was formally described in 1907 by the German ornithologist Anton Reichenow from a specimen collected in the Usambara Mountains of Tanzania.

[3] The specific epithet is from the Ancient Greek metōpias meaning "having a high forehead".

[5][6] Two subspecies are recognised:[6] The red-capped forest warbler is olive-brown above with a whitish color from the center of the throat to the vent, and with flanks that are washed grey.

The crown is a rich chestnut brown, as well as the ear-coverts and the sides of the neck.

The average adult is 10 cm long and has a mass of approximately 8.4 g.[7]