The prospective relations of temperamental effortful control and anger/frustration to Chinese children's (N = 425, age range = 6.6-9.1 years) academic achievement (grade point average, or GPA) and social adjustment (externalizing problems and social competence) were examined in a 2-wave (3.8 years apart) longitudinal study. Parents and teachers rated children's temperament, and parents, teachers, and/or peers rated children's externalizing problems and social competence. Effortful control positively predicted children's GPA, controlling for prior level of GPA. Analyses examining the potential mechanisms underlying the temperament-achievement associations suggested that effortful control positively predicted social competence, and social competence positively predicted GPA. Moreover, anger/frustration positively predicted externalizing problems, and externalizing problems negatively predicted GPA. Mediational analyses suggested that the relations between temperament and GPA were mediated by social competence and externalizing problems. Evidence for the reciprocal relations between externalizing problems and GPA was also found. The study suggested that there are complex interplays among temperament, academic achievement, and social adjustment for school-age children. (Contains 5 figures and 2 tables.)