The Nihoa Finch is very similar to the Laysan Finch but smaller. It has a yellow head, neck, and breast with a broad grey band between the neck and mid-back. The lower back and rump of the male are gray.
Females have a yellow throat and breast, the head and back is streaked with dark brown.
Its belly is white streaked with dark brown. It prefers open but vegetated habitat throughout the island. The Nihoa Finch builds its nests in small holes in rocks 100 to 800 feet above sea level. Egg laying begins in February and may extend to early June, with an average clutch of three eggs. This bird feeds on seabird eggs, insects, seeds, and flower buds.