The current study extends our understanding of the widely documented gender educational gap in favor of females and its contributing factors through a mixed-methodsanalysis of the Chinese case. We develop an analytical framework that incorporatesthree mechanisms—intergenerational social contract, non-cognitive skills, and cumulative (dis)advantage across the life course—to empirically assess gendered achievement patterns and their social mechanisms among Chinese adolescents. The Chinese Family Panel Studies data documented that adolescent girls have higher verbal and math achievements than boys, with the gap larger in verbal than in math scores. Three factors account for these gender gaps: (1) (grand)parents hold higher expectations for girls,monitor girls more closely, and invest in girls as much as in boys; (2) girls possess better non-cognitive skills; and (3) girls’ stronger performance in earlier years gives them an edge for later achievement. The in-depth interviews contextualize these statistical patterns in profound changes in families’ logic in supporting girls’ education and inreconfigured gender discourses about girls’ learning behavior. From the perspective of intergenerational contracts, in the context of low fertility, daughters have become cherished as long-term family members at the receiving end of intensive investment,particularly as educational competition intensifies in post-reform China. Moreover, a gender discourse, engaged by family members and teachers, about girls’ superior non-cognitive skills such as compliance and self-discipline exerts a powerful influence as a self-fulfilling prophecy with regards to girls’ achievement. The findings underscore the need to account for both cultural and policy contexts, and nuanced gender work at home and in school in understanding the gender-gap reversal in contemporary China.