Breeding males are bright lemon yellow with black crown, tail, and wings with white wingbars. The female is similar, though duller yellow, and without the black crown. The crown has no black, but the wings and tail are black. The wing bars are buffy. Lesser Goldfinches are less variable.
Males retain their black crown, green back, and yellow underparts in winter.
Females and immatures, too are brighter green than the brownish American Goldfinches in winter. Lessers have green rumps in flight, and large white wing patches. The black-backed male form is unusual in southern Idaho and at Malheur NWR, and rare elsewhere in the Northwest. In winter it retains its all-black back, crown, rump, and black and white tail and wings, and bright yellow underparts. Lawrence's Goldfinch has only been seen in Oregon once.