This thesis explores the information strategies of the League of Nations. Building on the recent literature on interwar international organizations and the related activities of non-state actors, I show how the first international bureaucracy had an uncomfortable relationship with public opinion. As officials downplayed their work in official publications, the League’s strategy in this field has long been called passive. In my research I show that, despite various restrictions and a ‘taboo’ on propaganda, League officials conducted an active lobby for the international organization. They stayed in close contact with individuals they considered opinion-shapers and tried to broaden the network of individuals promoting the League on their behalf. In this lobby, cooperation with the independent League societies is key. Officials traveled around the world to lecture about the League and adapted their message to national contexts. The actors made clear that a stable world order would only be achieved with the League managing international relations in the right direction.  Using the existing literature on the practices of the League’s Secretariat and the documents in eight archives in four countries, I look at four case study countries to see how the officials of the Information Section ventured into the world. These cases posed different challenges to the League’s section: officials encountered the struggle for self-determination in India, found a relatively willing public in the Netherlands, an ideological opposite in Italy, and tried to keep the United States, not a member, close to the international organization. The tensions between national and international loyalties become visible in the ways officials approached the public in these varying case studies. Comparing my findings with the work of other actors in the interwar period, I argue that the cooperation between the Information Section and the civil society organizations can be considered as the public diplomacy of the League of Nations.