This study examined the hypothesis that academic achievement affects different components of self-concept. Also investigated was the possible influence of nationality in modifying the relationship between academic achievement and self-concept, by comparing Slovenian and French subjects. The findings of two-factor (academic achievement x nationality) analyses of variance and discriminant analyses showed significant correlations between academic achievement and various indices of self-concept, which varied in a nationality-dependent fashion. The French subjects exceeded Slovenians in some domains of self-concept (i.e., verbal, academic, relations with same sex peers, relations with parents, religion and spirituality, and general self-concept) while Slovenian subjects exceeded French subjects in the domain of problem solving and creativity. There was no significant difference between the two national samples in self-esteem. Also, the French subjects exceeded Slovenian pupils in general academic achievement. The results were interpreted on the grounds of theoretical expectations related to the formation of self-concept and academic achievement, as well as on the basis of national differences in the school system and personality structure. The study concluded that national differences in self-concept domains are also related with auto- and hetero-stereotypes about French, British, and Slovenian people. (Author)