This special issue demonstrates the importance of interactions in transnational business governance. The number of schemes applying non-state authority to govern business conduct across borders has vastly expanded in numerous issue areas. As these initiatives proliferate, they increasingly interact with one another and with state-based regimes. The key challenge is to understand the implications of these interactions for regulatory capacity and performance, and ultimately for social and environmental impact. In this introduction, we propose an analytical framework for the study of transnational business governance interactions. The framework disaggregates the regulatory process to identify potential points of interaction, and suggests analytical questions that probe the key features of interactions at each point.