In historical writing the interwar years are often associated with the rise of extreme forms of nationalism. Yet paradoxically this period also saw significant advances in the development of internationalism and international-mindedness. This collection examines previously under-researched aspects of the role played by women’s movements and individual female activists in this process. Women campaigners contributed to, and helped to (re)define, what constituted international work in myriad ways. For some, particularly those coming from a radical pacifist background, the central theme after 1919 was the eradication of war and the preservation of world peace. Yet others were more interested in the sharing of medical knowledge across borders, in the promotion of new causes such as physical fitness or the cultural assimilation of immigrants, or in finding fresh and innovative ways of battling for old causes, such as female suffrage and women’s access to education. It was even possible for nationalist women to use the language and practices of internationalism to further their own conservative, illiberal or anti-communist agendas, or to argue for revision of the peace treaties of 1919-20. The volume addresses these different kinds of activism, and the many links between them, by way of particular examples. This book was originally published as a special issue of Women’s History Review.