In Africa, informal entrepreneurship sustains livelihoods and holds untapped potential for economic transformation, yet its transition to formal business remains underexplored. This study investigates the formalization processes of informal enterprises in Niger, a context marked by institutional fragility and socio-economic challenges. Grounded in institutional theory and using a longitudinal qualitative approach, the research identifies three key formalization strategies—administrative, managerial, and operational—shaped by the dynamic interplay of individual agency, organizational practices, and institutional environments. The findings highlight pathways for leveraging informality as a driver of structural development, offering actionable insights for policymakers aiming to integrate the informal economy into sustainable growth strategies.