Recent years have seen a growing scholarly interest in the conditions of emergence of regional trade agreements in Africa. These analyses have advanced our knowledge on a range of technical issues, from specific institutional transformation of regional economic communities such as the Economic Community of West African States (ECOWAS) to broad legal issues relating to the provisions of the regional trade agreements. Most literature on ECOWAS is, however, informed by legal formalism that interprets the text of the treaties strictly and without context, leading to a dominant interpretation of failure. By contrast, this thesis adopts a socio-legal approach and argues that the dominant narrative's conceptualization of ECOWAS is narrow and under-representative of the broader contexts of the social relations in which ECOWAS Treaties and their implementation are embedded. The failure narratives do not adequately account for the complex social, historical, and political factors that shape the implementation of the ECOWAS Treaties. By combining socio-legal approach with insights from International Relations on new regionalism, the thesis reconceptualizes regionalism in ECOWAS as a social phenomenon. It approaches the ECOWAS Treaties as embedded in the socio-political relations, power struggles, and social structures of the Community. To differentiate the thesis from existing research on ECOWAS, it incorporates national, regional, and international factors in illuminating the complex and multifaceted confluence of circumstances that shape the implementation of the ECOWAS Treaties. Simultaneously, the thesis enriches our understanding of the theories of new regionalism by deepening the analysis in relation to ECOWAS. Seen from this perspective, the thesis concludes that ECOWAS cannot be regarded as a straightforward failure and that its achievements are not to be found primarily in economic integration but in other socio-political factors that it enabled. Finally, the analysis opens new opportunities for future normative analyses that interrogate the effectiveness of ECOWAS by taking into account the socio-political contexts in which it is embedded.