The Black-chinned Hummingbird (Archilochus alexandri) is a small hummingbird.

Adults are metallic green above and white below with green flanks. Their bill is long, straight and very slender. The adult male has a black face and chin, a glossy purple throat band and a dark forked tail. The female has a dark rounded tail with white tips and no throat patch; they are similar to female Ruby-throated Hummingbirds.

Their breeding habitat is open semi-arid areas near water in the western United States, northern Mexico and southern British Columbia. The female builds a well-camouflaged nest in a protected location in a shrub or tree using plant fibre, spider webs and lichens.

They are migratory and spend most of the winter in Mexico.

These birds feed on nectar from flowers using a long extendable tongue or catch insects on the wing. While collecting nectar, they also assist in plant pollination.

Because of their small size, they are vulnerable to insect-eating birds and animals. This bird is fairly common in its breeding range.

A hybrid between this species and Anna's Hummingbird was called "Trochilus" violajugulum. The Black-chinned Hummingbird is also known to hybridize with Costa's Hummingbird.