Children adopted from institutions at older ages are at increased risk of persistent attention problems, lower cognition, and academic difficulties. This study examined cognitive and behavior problems as mediators of the association between early psychosocial deprivation and academic functioning. Participants were 8–17-year-old children adopted from psychosocially-depriving Russian institutions after 14 months of age (n = 34) and before 9 months of age (n = 39). Children completed a cognitive assessment, while their parents completed questionnaires on child behavior problems and use of learning support services in school. Children adopted after 14 months were found to have significantly lower vocabulary, higher levels of attention problems, and higher rates of using learning support services relative to children adopted before 9 months after controlling for age at assessment. The two groups did not differ significantly in nonverbal reasoning, anxiety, or oppositional behavior. Attention and vocabulary significantly mediated the association of early psychosocial deprivation with the use of learning support services. These findings suggest that interventions targeting attention regulatory and language skills may be beneficial in terms of improving school performance in this population.