The Dusky Flycatcher, Empidonax oberholseri, is a small insect-eating bird of the tyrant flycatcher family.

Adults have olive-grey upperparts, darker on the wings and tail, with whitish underparts; they have a noticeable medium-width white eye ring, white wing bars and a medium length tail. The breast is washed with olive-grey. The bill is mainly dark. It is a bit smaller than the Gray Flycatcher and a bit larger than the Hammond's Flycatcher.

Their breeding habitat is mountain slopes and foothills with brush and scattered trees across western North America. They make a cup nest low in a vertical fork in a shrub.

These birds migrate to southern Arizona and Mexico. As non-breeding residents in the south of their migration range, they are passage migrants over the deserts of the southwest US, the Mojave, Sonoran, and Chihuahuan Deserts, where they make their stops along the flyway.

They wait on an open perch and fly out to catch insects in flight, (hawking), also sometimes picking insects from foliage while hovering, (gleaning).

The call is a sad dew-hic.

The scientific name commemorates the American ornithologist Harry Church Oberholser.