The study is aimed to determine the differences in emotional intelligence, aggression, and academic achievement of adolescents with below average, average, and high average intellectual ability. Quantitative comparative study design was utilized and between groups comparison was made with 500 adolescent students, with equal male and female representation from different private secondary schools and colleges of Karachi. The participants completed Draw-A-Person Intellectual Ability Test for children, adolescents, and adults (DAP-IQ); Wong and Law Emotional Intelligence Scale (WLEIS); and Aggression Questionnaire-Short Form (AQ-12). Their academic achievement was assessed through their percentage of most recent examination and One-way ANOVA was utilized to examine the results. The results revealed significant differences in emotional intelligence and academic achievement of students with below average, average, and high average intellectual ability; however, an insignificant difference was found in their level of aggression. Hence, it can be concluded that, intellectual ability is an important factor in determining emotional intelligence and academic achievement of adolescent students.