The most populous country in Africa, Nigeria accounts for approximately one-quarter of West Africa's people. Although less than 25% of Nigerians are urban dwellers, at least 24 cities have populations of more than 100,000. The variety of customs, languages, and traditions among Nigeria's 250 ethnic groups gives the country a rich diversity. The dominant ethnic group in the northern two-thirds of the country is the Hausa-Fulani, most of whom are Muslim. Other major ethnic groups of the north are the Nupe, Tiv, and Kanuri. The Yoruba people are predominant in the southwest.

About half of the Yorubas are Christian and half Muslim. The predominantly Catholic Igbo are the largest ethnic group in the southeast, with the Efik, Ibibio, and Ijaw (the country's fourth-largest ethnic group) comprising a substantial segment of the population in that area. Persons of different language backgrounds most commonly communicate in English, although knowledge of two or more Nigerian languages is widespread. Hausa, Yoruba, and Igbo are the most widely used Nigerian languages.