This study examines the authoritarian ideology and educational policy of two dictatorial regimes of 20th century Greece: the Metaxas' dictatorship of 1936-1941 (the 4th of August regime); and the military junta of 1967-1974 (the 21st of April regime). Although viewed comparatively, the regimes in question are shown to have been different, due to crucial differences stemming from their contemporary international and domestic settings. Moreover, their ideologies were shaped by the way dictatorial rulers perceived and interpreted their reality. Influenced by the inter-war fascist context, the 4th of August regime tried to accommodate a radical fascist rhetoric to a nationalistic and traditionalist set of beliefs. Metaxas' perception of reality was exemplified in his educational policy, through which the dictator unsuccessfully tried to mobilise from above the youth, on the imported model of the fascist youth movements. The 21st of April regime contrasted sharply with the post-war international liberal environment, while its ideology was marked by the distinct and often contradictory mentalities of the colonels. The contradictions and inconsistencies of the military mind were reproduced at the educational level, as the military rulers attempted to demobilise a highly organised youth, to reverse the previous liberal educational reforms and to appoint loyalists to key posts. So, while the 4th of August saw the legitimation of its authority in the use of an openly authoritarian discourse and the mobilisation of the youth, the 21st of April regime, by contrast, torn by the conflicting mentalities of its military rulers, sought legitimacy through clientelistic networks of support and the demobilisation of the youth.