They are seed-eating birds with conical bills, brown or gray in color, and many species have distinctive head patterns.

A phylogenetic analysis of nuclear and mitochondrial DNA sequences published in 2015 found that the Passerellidae formed a monophyletic group that had an uncertain relationship to the Emberizidae.

[4] The International Ornithological Congress (IOC) recognizes 140 species in the family, distributed among these 30 genera.

Species in the neotropics tend to be much larger with bold patterns of greens, reds, yellows, and grays.

Given this huge expansive range, many species occupy different habitats such as grasslands, rainforests, temperate forests, and deserts and xeric shrublands.