This dissertation explores, from a transnational viewpoint, the historical relationship between war veterans and fascism in interwar Europe. Until now, historians have been roughly divided between those who assume that 'brutalization' (George L. Mosse) led veterans to join fascist movements, and those who stress that most ex-soldiers of the Great War became committed pacifists and internationalists. This dissertation overcomes the inconclusive debates surrounding the 'brutalization' thesis, by proposing a new theoretical and methodological approach, and offering a wider perspective on the history of both fascism and veteran movements. Drawing on a wide range of archival and published sources in five different languages, this work focuses on the interrelated processes of fascistization and transnationalization of veteran politics in interwar Europe. Firstly, it explains the connection between Italian Fascism and war veterans as the result of a process of symbolic appropriation of the notion of the 'veteran'. Then, it demonstrates that the cross-border circulation of the stereotype of the 'fascist veteran', and the diffusion of the 'myth of the fascist veterans', originating in the March on Rome, were crucial factors in the transnationalization of fascism and the fascistization of veteran politics in the 1920s. Furthermore, in the 1930s, networks of fascist veterans point to the existence of a transnational fascism, while new wars in Ethiopia and Spain strengthened the symbolic connection between veterans and fascism. Finally, the dissertation demonstrates that by 1939-1940, the fascist model of veteran politics was transferred into the new Spanish and French dictatorships. It is not 'brutalization', therefore, but rather a combination of mythical constructs, transfers, political communication, encounters, and networks within a transnational space that explain the relationship between veterans and fascism. Thus, this dissertation offers new insights into the essential ties between fascism and war and contributes to the theorization and conceptualization of transnational fascism.