The concept of “regime complexity” offers a valuable perspective for examining the interconnectedness of global governance institutions. This burgeoning field has un- covered networks of intersecting institutions across various policy realms, including trade, intellectual property rights, crisis management, and environmental policy. However, existing studies within regime complexity primarily emphasize state-centric and formal international organizational structures. This focus overlooks the critical roles played by non-state entities and informal, transnational arrangements. Such an oversight contrasts sharply with the general discourse in global governance, which underscores the significance of these emergent actors and structures in comprehending international relations. To bridge this analytical divide, the paper proposes a theoretical framework that integrates these diverse actors and organizational forms into the analysis of dynamics within regime complexes. This framework equips researchers with tools to systematically identify and understand the interactions among varied entities within these complexes. Additionally, it proposes theoretical predictions regarding the circumstances that influence actors’ strategic choices within these networks. As demonstrated, the applicability of the proposed framework through preliminary case studies in two regime complexes (internet governance and global health governance). The paper seeks to enhance the theoretical depth of regime complex analysis and better synchronize it with the wider discourse in global governance, thereby fostering greater theoretical integration between these two critical areas of study.