Brazil, Colombia, Ecuador, Guyana, Panama, Peru, Venezuela.
Locally in eastern Panama, Colombia, Venezuela, Guyana, western and eastern Ecuador, eastern Peru (south to Ayacucho), and northern Brazil (left bank of lower R Amazon).
 
Population
Estimated population is unknown (2010).
Sooty-headed Tyrannulet (Phyllomyias griseiceps) [XC511659]
by Peter de Rouw from Rio Silanche, Pedro Vicente Maldonado, Pichincha, Ecuador (call, song)
Sooty-headed Tyrannulet (Phyllomyias griseiceps) [XC303412]
by Andres Angulo from Caracara\u00ed, Roraima, Brazil (call)
Subspecies
No subspecies.
Genus as presently constituted may be polyphyletic. Anatomical evidence suggests that present species may be closest to Planalto Tyrannulet (Phyllomyias fasciatus) and Sooty-headed Tyrannulet (Phyllomyias griseiceps) and that all perhaps unrelated to others of genus, some or all of which possibly better placed in resurrected genus Tyranniscus.
Proposed subspecies cristatus (Panama, northern Colombia, northern Venezuela), caucae (middle and upper Cauca Valley, in Colombia) and pallidiceps (south-eastern Venezuela, southern Guyana, northern Amazonian Brazil, eastern Peru), described on basis of differences in length and colour of crown feathers and in wing length, considered unwarranted as variation in these characters at least as great among individuals from same regions as it is across huge geographical areas.