The majority of the population is African, but its composition is complex for a political unit so small in size. The Fang people, who fought their way to the sea in the 19th and early 20th centuries by subjugating the weaker tribes in their path, form about 80 or 90 % of the population of the mainland region. North of the Mbini River are the Ntumu Fang, and to the south of it are the Okak Fang. Holding political power on the mainland, the Fang tend to migrate to Bioko, where their leaders hold most of the levers of political control. Coastal tribes, such as the Kombe, Mabea, Lengi, Benga, and others, have been in contact with European traders much longer, and a limited amount of miscegenation has taken place, particularly on the island of Corisco. Spanish ethnographers refer to these coastal tribes as playeros. Both the Fang majority and the playero minority are Bantu.

The original inhabitants of Bioko are the Bubi, descendants of Bantu migrants from the mainland. Contacts with Europeans decimated them, and only a few thousand remained early in the 20th century. They became the most pro-Spanish element of the African population, viewing the end of Spanish rule as a signal for the invasion of their island by the Fang. Certainly, numbers of mainlanders, most of them Fang, have flocked to the island since the mid-1960s, seeking to join the civil or military forces or to obtain political patronage. In addition to these two groups, there are Fernandinos, descendants of former slaves liberated by the British during the 19th century who mingled with other emancipated Africans from Sierra Leone and Cuba as well as with immigrants from other western African countries.

Spanish and French are both official languages, though use of Spanish predominates. The Roman Catholic Church has greatly determined both religion and education. Equatoguineans tend to have both a Spanish first name and an African first and last name. When written, the Spanish and African first names are followed by the father's first name -which becomes the principal surname and the mother's first name. Thus people may have up to four names, with a different surname for each generation.