The rapid growth of e-commerce has intensified the need for data-driven marketing strategies, particularly among small and medium-sized enterprises (SMEs) operating in emerging economies. This study examines leveraging of big data adoption on marketing in Nigeria E-commerce landsacpe, Opportunities and challenges among Nigerian e-commerce SMEs, with a specific focus on customer acquisition effectiveness. Drawing on the Technology Organization Environment (TOE) framework, the study conceptualizes big data adoption across key dimensions, including data collection capability, analytical and interpretive skills, and technological infrastructure readiness. A quantitative research approach was employed, using survey data collected from owners, managers, and marketing personnel of Nigerian e-commerce SMEs. Data were analyzed using appropriate statistical techniques to assess the relationship between big data adoption and marketing outcomes.The findings reveal that big data adoption has a positive but uneven influence on marketing performance. While firms with stronger data collection and analytical capabilities experience improved customer targeting, personalization, and acquisition effectiveness, many SMEs fail to realize significant benefits due to infrastructural limitations, inadequate technical skills, and resource constraints. This study contributes to the literature by providing context specific empirical evidence from Nigeria, a setting that remains underrepresented in big data and e-commerce research. Practically, the findings highlight the need for SMEs to invest not only in data technologies but also in human capital development and organizational readiness