The negative reputation of women in mathematics and its consequences on their self-perceptions have been extensively demonstrated. However, in France and other countries, the younger the students, the less pronounced these gender differences are. The focus of this study was to explore whether children of two age groups (fourth graders and seventh graders) are aware of a math-ability gender stereotype favorable to boys, and to determine their personal beliefs on mathematics ability. The link between this gender stereotype and self-perceptions was also examined. As expected, there was not a clear-cut awareness of a math-ability gender stereotype favorable to boys. More surprising, girls in both age groups and seventh-grade boys believed that girls do better than boys. Moreover, when their gender identity was made salient, the boys who believed in girl superiority perceived their own performance in mathematics as lower. The girls, on the other hand, regardless of their age and stereotype awareness or personal beliefs, perceived their performance in math as higher when their gender identity was made salient than when it was not. © 2007 Springer Science+Business Media B.V.