This article argues that empirical developments in international security governance offer untapped opportunities for strengthening intellectual links between European Union (EU) studies and international relations. To uncover these links, the article first demonstrates how the EU has started to address various chemical, biological, radiological and nuclear security risks through adopting an approach conceptualized as ‘transnational security governance’. The article subsequently argues that this approach can be convincingly explained by drawing on the insights from the study of the sociology of bureaucracy and bureaucratic behaviour in international relations. In this story, the EU's approach to international security is an example of normal bureaucratic practice, stemming in particular from the bureaucracy's moral and expert authority. Importantly, the engagement with the broader social science scholarship will benefit EU studies as much as other sub-disciplines.