The Costa's Hummingbird (Calypte costae) is a species of hummingbird.

The Costa's Hummingbird is very small, a mature adult growing to only 3 to 3½ inches in length. The male Costa's has a mainly green back and flanks, a small black tail and wings, and patches of white below their gorgeted throat and tail. The male Costa's Hummingbird's most distinguishing feature is its vibrant purple cap and throat with the throat feathers flaring out and back behind its head. The female Costa's Hummingbird is not as distinct as the male, having grayish-green above with a white underbelly.

The Costa's Hummingbird is fairly common in the arid brushy deserts and any nearby gardens of the Southwestern United States and the Baja California Peninsula of Mexico.