Humanitarian aid has often been a malleable concept covering a broad range of activities. This article focuses primarily on emergency relief. It discusses existing narratives of international humanitarian aid and identifies crucial historical conjunctures during the twentieth century. It argues that neither the history of humanitarian organizations, nor aid as function of political economy, nor the evolution of global humanitarian governance provides a satisfactory historical explanation for the development of humanitarian aid during the twentieth century. Rather than such long-term narratives, the explanation is to be found in the turning points themselves, in historical conjunctures and contingencies. Three such conjunctures are explored: the post-World War I moment, the moment of postcolonial mobilisation, and the global interventionist moment.