Informal cross-border trade plays a significant role in regional integration within ECOWAS, particularly for Nigeria's economy. A mixed-methods approach combining qualitative interviews with quantitative data analysis to explore trends and patterns in Nigerian cross-border informal trade. Nigeria's informal cross-border trade constitutes approximately 20% of its total exports, highlighting the substantial economic impact of this sector within ECOWAS. While Nigeria faces challenges such as tax evasion and limited regulatory frameworks, it also presents opportunities for enhancing regional integration through targeted policy interventions. Nigeria should prioritise strengthening customs procedures, improving information sharing mechanisms among ECOWAS countries, and fostering a conducive business environment to enhance cross-border trade flows.