The Yellow Tyrannulet is found from Nicaragua to north and eastern Amazonian Brazil with seperate populations in western Ecuador and eastern Brazil but with sightings from a variety of sites in between.

A slender and long-tailed flycatcher, it is entirely yellow below, yellow-olive above with two broad yellow wing-bars and yellow edges to the wings. It has a long yellow supercilium.

There are illustrations in Ridgely & Tudor, Volume 2, Plate 34; Hilty & Brown, Plate 36; Ridgely & Greenfield, Plate 67 and Sick, Plate 35.