This article explores how Nigeria’s foreign policy has responded to transnational security challenges in West Africa. It engages in a conceptual overview of the discourse on transnational security and links this with a discussion of Nigeria’s foreign policy towards West Africa. Of note is Nigeria’s pursuit of a leadership role in the Economic Community of West African States (ECOWAS), in its quest for security, economic integration and development. Several questions are posed: What do Nigerian policymakers consider to be the most significant transnational threats in West Africa? How and through what legitimate policies and instruments do they respond to such threats? How important is ECOWAS to Nigeria’s attempt to respond to transnational threats? And how effective have Nigeria’s attempts to influence the ECOWAS agenda in this regard been? Although ECOWAS has remained central to Nigeria’s responses to transnational security threats in the subregion, the country has not been able to match its rhetoric on addressing transnational security threats with far-reaching concrete achievements. It is suggested that social transformation of Nigeria’s current foreign policy (that is, to one focused and committed to putting people at its centre) and a change in the policies of dominant global powers towards West Africa would enhance human emancipation and eliminate the numerous insecurities confronting the peoples of the subregion.