The chapter examines the history of the notion of national character in eighteenth-century France. Used initially in novels and plays to define an actor whose conduct could be predicted thanks to his ‘inner nature’, the concept was later used in historical writings to explain and understand, and even predict, the way entire nations acted. The main argument of this chapter is that, rather than being conceived as an unchanging and natural phenomenon, national character was increasingly understood as gradually changing throughout the ages, mainly thanks to education. Remarkably, many related the inclinations of individuals to those of the nation, a point that raised the issue of the individual’s freedom and his relationship with the community he was part of. Consequently, and especially from the 1730s onwards, the perceived decadence of France was related to the alleged debasing of the nation’s character, a fact that gave the notion a central place in all debates on political legitimacy. The chapter stresses that the national character was understood as a cultural frame within which the nation’s history deployed itself and which, albeit slowly, was also changing.