Compared with other parts of West Africa, Nigeria was slow to feel the penetration of Europe. Unlike in Ghana and Senegal, no European fortifications were built along the coast, and Europeans - mostly British - came ashore only briefly to trade weapons, alcohol, and other goods in return for slaves.

In 1807 Britain abolished the slave trade and enlisted other European nations to enforce the ban. The British Empire no longer had American colonies whose economic growth depended on slaves, and moreover the rise of industrialization meant Britain needed Africa's raw materials more than its people. Consequently, trade in products such as palm oil, which Europeans valued highly as an industrial lubricant, replaced the trade in humans. Most of Nigeria's former slave-trading states were weakened by the loss of income.

British trading companies such as the United Africa Company took advantage of the weakened empires and established depots at Lagos and in the Niger Delta. Meanwhile, explorers such as Mungo Park and Hugh Clapperton of Scotland, John and Richard Lander of England, and Heinrich Barth of Germany charted the Niger River and its surroundings. The explorers, some of them funded by trading companies, laid the groundwork for the eventual expansion inland of the trading companies. Missionaries also facilitated the process of replacing the noxious slave trade with 'Christian commerce'. Some inland peoples took advantage of new opportunities to produce goods for the Europeans, but most resisted and were forcibly subjugated.