BACKGROUND: Adolescence is a period of physical, nutritional, and sexual transition, also remarkable for the accompanying psychological changes. Worldwide, 20% of children and adolescents suffer from a disabling mental illness. Therefore, knowledge of the prevalence of these disorders can be used to design intervention strategies. The present study was conducted in the 13-15 years’ age group schoolgoing adolescents, with the objective to estimate the prevalence of psychological morbidity, employing Strength and Difficulties Questionnaire (SDQ). MATERIALS AND METHODS: A cross-sectional analytical study was conducted in three different schools of Aligarh, in the 13-15 years’ age group, with a prior permission from the school authorities. The study was approved by a multidisciplinary Institutional Ethics and Research Advisory Committee. RESULTS: A total of 1456 students were sampled for the study. The prevalence of psychological morbidity on the basis of total difficulties score was found to be 9.75% (95% confidence interval – 8.33-11.39). The prevalence of emotional, conduct, hyperactivity, peer, and prosocial problems was 5.42%, 5.56%, 3.78%, 4.40%, and 4.26%, respectively. CONCLUSIONS: Psychological problems are fairly common in the adolescent age group. Despite the need, there is a dearth studies conducted in this crucial age group in India. Of the studies available, a wide variance is reported either due to the difference in diagnostic tools or due to the types of psychological disorders considered in different researches. For the purpose of uniformity and comparability, SDQ stands as a good option.