The text analyzes the work of the International Union for Child Welfare (IUCW), founded in 1919, and the role of its delegates, most of whom are social workers. The organization, created to help European children after World War I, then sought to extend its activities to (post)colonial territories. These women became intermediaries between humanitarian circles, politicians, and local elites, with a mission combining social aid and diplomacy. The article shows that their practices often remained influenced by a Western vision of a “civilizing mission.” The case of Frédérique Small in Ethiopia illustrates both the professional audacity of these delegates and the tensions with imperial logic. The case of Jeanne-Marie-Small and her exchanges with Zahia Marzouk in Egypt offers a second insight. After 1945, the UISE attempted to internationalize, but its networks remained Eurocentric and struggled to adapt to decolonization movements or to respond to the needs of Egyptians, who had their own social work infrastructures. Thus, despite its universalist ambition, the organization remained limited by postcolonial power relations, and its ambition and discourse could therefore be largely nuanced by this observation of marginalization.