Plumbeous-crowned Tyrannulet is a small flycatcher of montane northwestern South America. Distributed from Colombia south to Peru, this bird inhabits middle levels and canopy of montane forest from 1300 to 2200 meters in elevation. It has a blue gray crown, olive upperparts, blackish wings with yellow wing bars, a gray face with a darker auricular frame, and white throat that blends into a gray chest and yellow belly and flanks. Plumbeous-crowned Tyrannulet is superficially similar to several other species of flycatcher, and would be easy to overlook, except for its loud, distinctive calls. Even so, Plumbeous-crowned Tyrannulet is a very poorly known species, and almost nothing is reported on its natural history.