The planalto tyrannulet (Phyllomyias fasciatus) is a species of bird in subfamily Elaeniinae of family Tyrannidae, the tyrant flycatchers.

[2] The planalto tyrannulet has three subspecies, the nominate P. f. fasciatus (Thunberg, 1822), P. f. caerae (Hellmayr, 1927), and P. f. brevirostris (Spix, 1825).

P. f. caerae resembles brevirostris but has a darker brown crown, duller and less yellow upperparts, and underparts midway between those of the other two subspecies.

[4][5][6] The nominate subspecies of the planalto tyrannulet is found in eastern Brazil in an area bounded roughly by eastern Pará, western Bahia, southern Mato Grosso, and southern Goiás and from there into extreme northeastern Bolivia in Santa Cruz Department.

Subspecies P. f. brevirostris is found in southeastern Brazil from Minas Gerais and Espírito Santo south to Rio Grande do Sul, in eastern Paraguay, and in northeastern Argentina's Misiones Province.

[4][5][6] The planalto tyrannulet is a year-round resident in most or all of its range; there is some evidence that the population in Rio Grande do Sul moves north after the austral summer.

In the southeastern part of its range it sings "a slow series of 3-4 slightly descending, plaintive 'puh-puh--' minor-key notes".