The tricolored blackbird (Agelaius tricolor) is a passerine bird of the family Icteridae. Its range is limited to the coastal areas of the Pacific coast of North America, from Northern California in the U.S. (with occasional strays into Oregon), to upper Baja California in Mexico.

This highly social and gregarious bird forms the largest colonies of any North American landbird, with a single breeding colony often consisting of tens of thousands of birds.

The common name is taken from the male bird's distinctive white stripes underneath their red shoulder patches, or "epaulets", which are visible when the bird is flying or displaying.

Despite the similar names, this bird is not related to the Old World common blackbird, which is a thrush (Turdidae).

The species' call sounds slightly more nasal than that of the red-wing's - a nasal kip and a sharp check. The male's song is a garbled on-ke-kaaangh. The bird migrates south during the colder seasons to Mexico and back to northern California during the warmer seasons.