This article develops a novel theoretical framework to analyse the mandate, implementation, and effectiveness of the Intergovernmental Authority on Development (IGAD) Security Sector Programme (ISSP) in non-member states, with a specific focus on Madagascar. It critiques the limitations of existing regional security complex and security sector reform theories when applied to such hybrid engagements. The proposed framework synthesises concepts of extra-regional actorness, transnational bureaucratic authority, and adaptive hybridisation to explain the programme's operational dynamics and contested outcomes. The analysis concludes by outlining the framework's implications for understanding regional organisations' roles in complex African security landscapes and its practical utility for policymakers.