The land boundary between Nigeria and Cameroon extends for 2,062 km from Lake Chad in the north to the Gulf of Guinea in the south. It has a complicated colonial history with boundaries originally established between German (Kamerun) and British (Nigeria) powers, but after World War II, governance of Cameroon was transferred from Germany to France (French Cameroon) and the United Kingdom (Northern and Southern Cameroons). The modern-day state of Cameroon would not be fully complete until after a 1961 plebiscite in which British Northern Cameroons joined French Cameroon.

In 1994, Cameroon instituted proceedings against Nigeria at the International Court of Justice for a land and maritime dispute. Nigeria had begun to claim and occupy territory around Lake Chad and the entire Bakassi Peninsula in addition to its adjacent oil rich maritime territory. Seventeen smaller boundary conflicts between Lake Chad and the Bakassi Peninsula were also brought before the Court. In 2002, a judgment was made that generally upheld the colonial boundary documents and provided clarification on their interpretation on several points. Despite the Court’s ruling, it took an additional four years for Nigeria to recognize Cameroon’s sovereignty over the Bakassi Peninsula and another seven for the full transfer of administration. There are still occasional, mostly local, conflicts in the area.

As of 2019, the majority of the land boundary has been demarcated with oversight and assistance provided by the United Nations. The process has been slowed somewhat due to instability in the northern border region caused by Boko Haram, an Islamic militant group operating in Northern Nigeria, and there are a few areas of disagreement between the two governments on the precise location of the international boundary.

Cameroon and Nigeria also have an established maritime boundary.