This species was formerly considered conspecific with the cinnamon-rumped seedeater (Sporophila torqueola), with the combined species known as white-collared seedeater.

However, with the discovery that cinnamon-rumped and Morelet's are deeply divergent from one another genetically, don't intergrade, and aren't even each other's closest relatives within the genus, they are now treated as separate species.

[2][3] It ranges from a small area along the Rio Grande near San Ignacio, Texas in the United States[4] south through eastern Mexico and Central America to Panama.

It mainly inhabits tropical and subtropical grasslands, savannas, and shrublands but can also be found in pastures, arable land, and heavily degraded former forests.

[1] The Morelet's seedeater eats mainly seeds and insects, and occasionally berries.