In the 1980s social sustainability found a clear conceptualization based on local community engagement and cultural diversity promotion. Recently the UN’s World Tourist Organization (UNWTO, 2019), focusing on participatory processes, has recognized destination management organizations (DMOs) as key players in designing sustainable tourism. Despite its importance, tourism historians have only occasionally paid attention to the issue and DMOs have usually been studied more to assess their impact on promotion than on sustainability. This paper is a first attempt to put the social sustainability issue into an historical perspective by focusing on DMOs in France and Italy, from the interwar years to the 1970s. In Italy DMOs made their appearance in 1926 (they were called Azienda di soggiorno, cura e turismo) and soon started to design concerted tourism strategies at the municipal level involving local stakeholders, as the case study of Rimini and Riccione shows. They became a driver for social sustainability. Where tourism development was driven by the state, it was impossible to set up real DMOs and this also impacted social sustainability as the experience of Latina province reveals. Since the mid-1960s changes in mass tourism (media, advertising, transport) have pointed to the advantages of scaling strategies at the regional level. Italy and France have chosen different solutions, making the task of guaranteeing social sustainability more complex.