This study was undertaken to compare social adjustment and academic achievement of female children with secure and insecure attachment patterns. The research type was descriptive, causal-comparative. The statistical population of the study included all 10-12-year-old elementary school girls in Tehran in academic year 2014-2015. The statistical sample consisted of 205 students who were selected through multistage cluster sampling method. The instrumentation comprised Matson Evaluation of Social Skills with Youngsters, Ronaghi’s Attachment Scale of Middle Childhood as well as Dortaj’s Academic Performance Questionnaire. For the purpose of data analysis, independent samples t-test and multivariate analysis of variance were used. The results showed that there was a significant difference between attachment styles, social adjustment, and academic achievement of children with secure and insecure attachment patterns (p<0.001) and the highest level of social adjustment and academic performance was observed among children with secure attachment style. It can be concluded that attachment styles influence children's academic performance and social adjustment and strengthening parent-child relationships can boost children’s social adjustment and academic performance.