The Grey-lined Hawk is marginally bigger than the more common Roadside Hawk (Rupornis magnirostris), is an overall grey with fine white barring below, has white bands across its tail and yellow legs and cere.

It is found from New Mexico and Texas through Central and South America as far as Paraguay and northern Argentina. Throughout this range it is found in a wide variety of habitats from the edge of rain forests to dry, open scrub country.