After over two decades of the revision of the Economic Community of West African States (ECOWAS) treaty, which stipulated a common market, including a common external market, the Head of States of the Community as part of fast-tracking their regional integration process and laying the grounds for the establishment of an effective Customs Union decided to implement the ECOWAS common external tariff (CET) in early January of 2015. The CET, which requires the adoption of the same customs duties application to all goods entering ECOWAS Member States, regardless of which country within the area they are entering also requires careful preparation and communication by member ministries. The adoption of the CET according to trade experts will also prompt reaction from firms and producers, as external competition from imports will change. Despite the myriad of challenges facing the Community and its consciousness of the overriding need to accelerate, foster and encourage the economic and social development of their states in order to improve the living standards of their peoples, the question that needs to be addressed is “What has contributed to the lagging behind of the implementation of the Community’s ambitious regional integration policies and targets compared to the European Union process-oriented integration theory given that a common trade policy does not only define the trade relations with the third-parties but also with the member States within the internal market?.