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

Adults have olive-brown upperparts, browner on the wings and tail, with whitish underparts; they have a white eye ring, white wing bars, a small bill and a short tail. The breast is washed with olive-grey. The upper part of the bill is grey; the lower part is orangish. At one time, this bird was included with the very similar Willow Flycatcher in a single species, "Traill's Flycatcher".

Their breeding habitat is deciduous thickets, often alders or willows, near water across Canada, Alaska and the northeastern United States. They make a cup nest low in a vertical fork in a shrub.

These birds migrate to South America, usually selecting winter habitat near water.

They wait on a perch near the top of a shrub and fly out to catch insects in flight, also sometimes picking insects from foliage while hovering. They may eat some berries and seeds.

This bird's song is a wheezed wee-bee. The call is a quick preet.