Introduction: Relation between constructing complex mental structures and language skills cause delays in development of executive functions of deaf children. When the importance of language skills in development of executive functions and frequency of aggressive behaviours of deaf children are considered, investigation of executive functions of deaf children may explain their aggressive behaviours. Method: 82 children of 10-14 ages were analyzed within 2 groups; students with and without early special education background. For measuring aggressive behaviours Buss-Durke Hostility Inventory (BDHI) and for measuring executive functions Wisconsin Card Sorting Test (WCST) were used. Results: Preschool special education has no significant effect on aggressive behaviours but on executive functions. Aggression has no significant effect of any variables analyzed in the present study whereas early special education background and gender has significant effects on the development of executive functions. Discussion and Conclusions: From a theoretical perspective, the findings support the interdependence of language and executive functions. Therefore, one can say that early special education has positive effects on cognitive development of deaf children, however, lacks of supporting social development during adolescence. (Contains 6 tables.)