Background. It is well established that children's self-evaluation bias of competence is related to the quality of parent-child emotional relationship. Such biases are linked to children's academic functioning and achievement. Links have also been established between the quality of parent-child emotional relationship and children's academic functioning. No study has yet explored how the effects of children's emotional relationship with their parents and children's self-evaluation bias combine to explain their academic functioning. Aims. The first goal was to examine whether the quality of parental emotional support reported by both children and parents was related to the children's self-evaluation bias of competence. The second goal was to examine the relationships between children's and parents' reports of emotional support, and children's academic functioning as measured by teachers' report of their motivation, self-regulation of school activities, and academic achievement. The third goal was to determine whether a children's self-evaluation bias mediated the relationship between parental emotional support and academic functioning. Sample. In a 2-year longitudinal design, participants were 524 elementary pupils (grades 4 and 5), one of their parents, and their teachers. Results. Our results indicated that a bias in self-evaluation in the first year of the study mediated the relationship between the quality of parental emotional support assessed at the first year and their school functioning evaluated by their teacher 1 year later. Conclusion. The mediational model received clear support when it refers to the emotional support reported by children, but mixed support when reported by parents.