<p>This study examines how entrepreneurial ecosystem components influence the sustainability of small scale fintech firms in Nigeria. Drawing on entrepreneurial group theory, we focus on four ecosystem dimensions, culture, human capital, network relationships and government policies, and investigate their effects on the ability of small fintech firms to maintain operations, grow and adapt over time. Data were collected through a structured questionnaire from 197 owner-managers of small scale fintech firms and analysed using structural equation modelling with AMOS. The results show that culture, human capital, networks and government policies all have significant positive effects on fintech sustainability, with network relationships exerting the strongest influence. These findings highlight the central role of group based networks and capabilities in translating ecosystem conditions into sustainable outcomes for small fintech firms in an emerging economy. The study contributes to entrepreneurial ecosystem research by applying entrepreneurial group theory in a fintech context and offers practical implications for policymakers and ecosystem actors seeking to support the long term viability of small scale fintech businesses.</p>