The yellow-bellied flycatcher (Empidonax flaviventris) is a small insect-eating bird of the tyrant flycatcher family.
Adults have greenish upperparts and yellowish underparts (especially on the throat), with a dusky wash on the chest. They have a white or yellow eye ring that lacks the teardrop projection of Pacific-slope (E. difficilis) or cordilleran (E. occidentalis) flycatchers, white or yellowish wing bars that contrast strongly against the black wings, a broad, flat bill, and a relatively short tail when compared to other members of the genus. The upper mandible of the bill is dark, while the lower mandible is orange-pink. DNA testing in 2014 confirmed a field mark, involving the extent of buffy edging on the secondaries, to reliably distinguish this species from the two so-called "Western Flycatchers."