The black-rumped waxbill (Estrilda troglodytes) is a common species of estrildid finch found in Southern Africa.

It is found in Benin, Burkina Faso, Cameroon, Central African Republic, Chad, The Democratic Republic of the Congo, Côte d'Ivoire, Eritrea, Ethiopia, France (introduced by Guadeloupe), Gambia, Ghana, Guadeloupe, Guinea, Kenya, Liberia, Mali, Mauritania, Niger, Nigeria, Portugal (introduced), Puerto Rico, Senegal, Sudan, Togo, Uganda, United States (introduced in Puerto Rico) and Virgin Islands (possibly extirpated).

The black-rumped waxbill was first described by Hinrich Lichtenstein in 1823, and at the time was placed in the Fringilla genus.

[2] When the Estrilda genus was described in 1850, this species was moved there.

[3] It was at one point thought to be conspecific with the Arabian waxbill.