This widespread and abundant species is often found around human habitation, often with other species such as the red-cheeked cordon-bleu, and its soft queet-queet call is a familiar African sound. The song is a rising chick-pea-pea-pea.
The red-billed firefinch is a small gregarious bird which feeds mainly on grain and other seeds. It frequents open grassland and cultivation. The nest is a large domed grass structure with a side entrance, built low in a bush, wall or thatch into which three to six white eggs are laid. The nest of this species is parasitised by the village indigobird.