Drawing on personality psychology research, Dornyei and his colleagues have recently developed an approach to understanding L2 motivation that positions the learner's self-recognition as a potential communicator in another language at its core, thus marking a break from the established social psychology paradigm. In this article it is argued that, in the application of Dornyei's Motivational Self-System model, gender is of particular importance. To analyse the effects of gender on the development of compulsory school pupils' L2 self-concepts, a questionnaire was administered to a Swedish cohort (N = 169) at two points in time; after one and four years of FL learning. Whilst the results for the whole sample indicate that pupils' self-concepts remain stable over the period, separate analyses reveal that girls' self-concepts strengthen whereas boys' weaken. This suggests a Gender X Age interaction in the trajectories of L2 self-concepts and "gender role intensification". Additionally, early L2 self-concepts were found to have good predictive qualities. The results underscore the importance of including gender as a key variable in future research conducted within the motivational self-concept paradigm. Further, the gender-role intensification evidenced in this study suggests that European policies of plurilingualism may have negative effects on boys' overall academic self-concepts. (Contains 10 tables.)