This chapter explores the relationship between Spain and the Axis powers during the Second World War. Spanish experts were involved in intensive exchange with Nazi Germany during the war. This formed part of a wider pattern of cooperation between Axis, Axis-aligned, and neutral states under the auspices of the Nazi ‘New Order’. This chapter argues that the scientific networks, conferences, and organizations promoted by Nazi Germany represented a form of ‘Axis internationalism’, which appropriated the language and practices of pre-war internationalism to promote the idea of collaborative continental order under Nazi leadership. Spanish experts, like many of their European counterparts, were willing to embrace Axis internationalism as a new, and in many ways improved, form of international cooperation. Their work highlights how internationalist structures and ideas, particularly within the ‘technical’ and humanitarian fields of health and medicine, could be appropriated by political projects from across the ideological spectrum.