The Gray-capped Tyrannulet is a small flycatcher endemic to eastern Brazil. The species is found in edge habitats and scrub below 1600 meters in elevation. It has a blue-gray cap, pale gray face, olive upperparts with black wings with coverts and flight feathers edged yellowish, olive chest, yellow flanks, and white belly. A member of the genus Phyllomyias, this is a difficult species to identify as there are a number of similar species; however, it is more brightly marked than most of its congeners. Found both on its own as well as in mixed flocks, the Gray-capped Tyrannulet can sometimes be detected by its quiet, mellow whistled call, though it is often silent.