The Barrow's Goldeneye is a medium-sized diving duck. They have a yellow eye, a steeply sloped forehead with flatter crown and peak at forward part of crown. They have a small, stubby bill.
The bill of the female Common Goldeneye is larger and mostly black with a yellow tip, while the Barrow's bill is smaller and mostly yellow. Male Barrow's Goldeneyes have iridescent purple heads that look black when not in the sun, and prominent, crescent-shaped white spots on each side of the head at the base of the bill.