This paper seeks to discuss the influence of South Asian decolonisation movements on European pacifism in the interwar period through the work and ideas of Pierre Ceresole (17/08/1879 – 23/10/1945), a Swiss internationalist and pacifist. In exploring how his ideas about pacifism evolved in relation to World War I and its aftermath, this paper argues that anti-colonial nationalism and decolonisation movements played a crucial role in shaping his pacifist methods and networks. The paper seeks to link two strands of historical research: first, the role of religion and spirituality in humanitarianism, and second, how activities that went against dominant discourses of nationalism, colonialism and ideologies of violence were shaped by interaction between civil society groups in transnational thought zones throughout the first half of the twentieth century.