This article complements the doctrine of termination of membership by arguing that at times international organizations (‘ios’) can still exert considerable normative effects on states that withdraw or express the intent to withdraw from them. We capture this continuing influence, which can collide with the exiting state’s intended goal of regaining control over specific issues, with a theoretical framework based on juridification as a socio-legal concept of systems theory in the international legal context. The aim is to explain the endogenous process of legal growth within the io via bureaucratisation and expert rule, which eventually affects the norms of the wider legal regime where the io operates. With three case studies of io exits, we illustrate the continuation of normative structures promoted directly or indirectly by the io, according to two legal techniques of juridification: third-party interpretation on the one hand, and the extended reach of norms and processes through the work of non-state actors on the other. Overall, widening the theoretical perspective on state exits under systems theory can lead to more complete judgements on the tensions between domestic and supranational systems in the expansion of global normative regimes.