The Sooty Grassquit (Tiaris fuliginosus) 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, Guyana, Paraguay, Trinidad and Tobago, and Venezuela. Its natural habitats are subtropical or tropical moist lowland forests, subtropical or tropical moist montane forests, subtropical or tropical dry shrubland, and heavily degraded former forest.