The article addresses international efforts at child protection, emphasizing the criminal law on juveniles before 1914, and focuses on key international organizations and their various conferences and congresses. Although there was an institutional divide between welfare in general, child protection and youth crime, the organizations covered similar topics with regard to juvenile criminal law. The article investigates two aspects of the process by which the field became internationalized. First, it describes the people and institutions that disseminated the idea of juvenile criminal courts and the various strategies they developed to create an international forum for the issues surrounding them. Second, it describes how various measures were adapted, appropriated and implemented, using Germany as an exemplary case. In general, the article attempts to contribute to the emerging field of transnational history, which emphasizes cross-boundary relations, interactions and interdependencies beyond the nation state.