Mobile money has transformed financial access in West Africa, yet small and medium sized enterprises (SME’s) continue to exhibit low sustained adoption despite high initial intention. Dominant theories such as the Technology Acceptance Model, Unified Theory of Acceptance and Use of Technology, and Diffusion of Innovations focus primarily on pre-adoption behavioral intention and fail to explain the multi-stage transition from cash-dominant routines to full institutionalization. This conceptual paper addresses this gap by adapting Technology Transition Theory originally developed to explain sustained use of collaborative technologies to the West African SME context. The suggested framework uses three stages to model adoption as a continuous process: Pilot Long-Term Use and Institutionalization. Progression is governed by the multiplicative equation Acceptance = Magnitude × Frequency of perceived net-benefits, moderated by West Africa-specific factors including agent networks, regulatory fragmentation, trust, digital literacy, informality, and owner-manager influence. Ten testable propositions link these elements to outcomes such as enhanced financial inclusion, operational performance, and economic resilience. The framework bridges intention based and process-based theories, offering the first explicit transition-oriented model for SME mobile payment adoption in the ECOWAS/WAEMU region. It provides actionable guidance for SMEs, mobile money operators, fintech providers, and policymakers, emphasizing phase-specific interventions, regulatory harmonization, and incentives for institutionalization. Future empirical research should employ longitudinal designs, multi-country comparisons, and mixed methods approaches to validate and refine the model, advancing both theory and practice in inclusive digital transformation across West Africa.