The Dull-coloured Grassquit (Tiaris obscurus) is a small bird formerly placed with the Emberizidae. It is now recognized as a tanager closely related to Darwins finches.

It is found in Argentina, Bolivia, Brazil, Colombia, Ecuador, Paraguay, Peru, and Venezuela. Its natural habitats are subtropical or tropical moist lowland forests, subtropical or tropical moist montane forests, subtropical or tropical moist shrubland, subtropical or tropical high-altitude shrubland, and heavily degraded former forest.