[6][7] Four subspecies are recognised:[7] The adult yellow-green vireo is 14–14.7 cm in length and weighs 18.5 g. It has olive-green upperparts and a dusky-edged gray crown.

This vireo occurs in the canopy and middle levels of light woodland, the edges of forest, and gardens at altitudes from sea level to 1500 m. The 6.5-cm-wide cup nest is built by the female from a wide range of plant materials, and attached to a stout twig normally 1.5–3.5 m above the ground in a tree, but occasionally up to 12 m high.

The normal clutch is two or three brown-marked white eggs laid from March to June and incubated by the female alone, although the male helps to feed the chicks.

The breeding birds return to Central America from early February to March, and most depart southwards by mid-October.

They also eat small fruits, including mistletoe berries, and, in winter quarters, those of Cymbopetalum mayanum (Annonaceae) and gumbo-limbo (Bursera simaruba).