Abstract:Evidence from several studies illustrates the different points of view through which sustainability and mountains have been studied over the years. Nowadays, interest in Millennials is increasing but no research has compared Millennials and sustainability in the mountain context. This study aims at defining sustainability with reference to Millennial perception of both winter and summer mountain sports. By analysing data gathered from a sample of 2292 Millennials (Piedmont area), the authors confirm their high degree of sensitivity towards sustainable issues and, above all, discover that there are differences in the sustainable perception Millennials have of both mountain winter and summer sports. More specifically, Millennial perception is deeply influenced by the place where they are used to living-mountains or cities-and by their gender. From a managerial point of view, results have direct implications on the administrators of mountain institutions who can implement appropriate initiatives in order to correctly sensitise Millennials towards mountain sports. Moreover, from a theoretical perspective, the study opens a new scenario on two important topics linked to sustainability, namely Millennials and mountain sports.