This chapter examines the organization and operations of the International Peace Campaign (IPC) or Rassemblement universel pour la Paix (RUP) and its China National Committee during the 1930s and the first years of the Second Sino–Japanese War (1937–1945), a key theatre of World War II. Established in 1936 and encompassing forty-three member states, the IPC/RUP became a major anti-fascist movement organized by British and French activists. Despite its importance, most histories of peace efforts in the 1930s only comment briefly on the laudable but ultimately ephemeral nature of the organization’s efforts in challenging the rise of fascism and endorsing collective security under the League of Nations framework. Some suggest that it ultimately proved to be a disruptive force, creating organizational problems for such established peace groups as the League of Nations Unions (LNU) in Great Britain. 1 Concerned with the IPC’s failure to help prevent the fall of the Spanish Republic, most scholars have overlooked the organization’s activities in China. Yet the IPC’s response to Japanese aggression in China and the evolution of its China National Committee illustrates the global scope and dilemmas of peace activism in the interwar years.