The entrepreneurial ecosystem in Guinea presents significant challenges for small and medium enterprise (SME) development, characterised by fragmented support services, limited access to finance, and infrastructural deficits. These constraints hinder sustainable business growth and economic diversification. This study aimed to develop and iteratively test a participatory action research framework to enhance SME resilience and growth within the local ecosystem. Its objectives were to identify systemic barriers, co-design interventions with entrepreneurs, and evaluate the framework's efficacy in improving business capabilities. An action research methodology was employed, involving four iterative cycles of planning, acting, observing, and reflecting. Data were collected through participatory workshops, in-depth interviews, and longitudinal case studies with 42 SME owners across three regions. The co-developed interventions led to measurable improvements in participants' financial management and market access. A key theme was the critical role of trusted local intermediaries in facilitating ecosystem navigation. Specifically, 71% of participating enterprises reported enhanced access to new customer segments following the implementation of peer-network strategies. The action research framework proved effective in fostering practical, context-specific solutions for SME development. It underscores the value of collaborative, practitioner-led inquiry in addressing complex entrepreneurial challenges within constrained environments. Policymakers and business support organisations should institutionalise participatory, iterative learning processes. Future programmes must prioritise the strengthening of local intermediary networks to improve ecosystem coordination and resource flow. Action research, entrepreneurial ecosystem, business development, small and medium enterprises, Guinea, West Africa This paper provides a novel, empirically tested action research framework for designing and implementing business development interventions in complex, resource-constrained African economies.