In recent years the term ‘humanitarian diplomacy’ has become fashionable among humanitarian organizations in general, and within the Red Cross and Red Crescent Movement in particular. However, the very idea of ‘humanitarian diplomacy’ is not uncontroversial, owing to the imprecise and contested nature of the term, and to its unclear operational application. The present article proposes to explore the definitions and scope of action of humanitarian diplomacy, as well as some of the challenges that it faces, with a view to preparing the way for its eventual recognition by the international community.