Of the five major black African ethnic groups in Mauritania, the largest is the Toucouleur, an offshoot of the Fulbe. The Fulbe are the second largest black African group in the country. Other significant black African groups include the Soninké, Wolof, and Bambara. Small groups of other ethnic Africans also live in the far south of Mauritania.

Like Maures, most Fulbe are nomadic. Most other African groups practice sedentary agriculture in the Senegal River Valley. Almost all have kin in Senegal or Mali. They speak Fulfulde or West Atlantic languages within the Niger-Congo language family.

Black African society, like Maure society, is highly stratified. The overall system of social stratification is nearly identical for all black groups. Three classes predominate: nobles, endogamous castes, and a servile class. Further social distinctions are recognized on the basis of livelihood, prestige, and power. Castes of skilled craftsmen are organized on the same occupational basis as among the Maures. Slaves and former slaves compose the servile group, but as within Maure society, they are accepted as part of a family and enjoy relatively humane treatment.

Data as of June 1988