The purpose of the present study was to examine mechanisms by which the characteristics of child temperament influences academic achievement in late childhood. It was hypothesized that the effects of child temperament on achievement would be mediated by assertive behavior on the part of children and maternal parenting behavior. Data for this study came from self-report questionnaires completed by 657 elementary school children (343 boys, 314 girls). The results of structural equation modeling demonstrated that child temperament affected academic achievement through both assertive behavior and maternal parenting behavior; this was evidenced across the entire sample. Child temperament (approach-withdrawal, mood quality, persistence) also had a number of positive effects on assertive behavior (directiveness, social assertiveness, defense of rights and interests) and maternal parental behavior (warmth-acceptance, guidance). These results were found to be the case for both boys and girls. The results of this study further revealed that maternal parenting behavior mediated the relationship between child temperament and achievement for boys, whereas assertive behavior played the same role for girls. These findings suggest the need for different approaches in developing programs to improve levels of academic achievement which give due consideration to child temperament and social behavior as well as parenting, based on child gender.