Informal cross-border trade plays a significant role in regional integration within Economic Community of West African States (ECOWAS), highlighting its importance for enhancing economic ties and development across member states. The analysis employs qualitative research methods, including case studies and interviews with key informants from both government agencies and private sector entities involved in cross-border trade within ECOWAS. A notable finding is the substantial proportion (35%) of total intra-regional trade that consists of informal transactions across borders, underscoring their critical economic significance. The study concludes by emphasising the need for harmonized policies to facilitate smoother cross-border trade and enhance regional integration within ECOWAS, particularly in light of decentralization trends in Ethiopia. Recommendations include developing a comprehensive regulatory framework that supports both formal and informal cross-border trade activities, thereby fostering economic growth across member states.