This study was studied that emotional and behavioural problems of young students who are directly related to their academic achievement and thus play a vital role in the development of young learners carrier. This study helped to fill a gap by conducting an exploration of psychological adjustment and academic achievement among adolescents. It also examined the gender differences on psychological adjustment and academic achievement. Purposive sampling technique was used in this study with sample size of one hundred and twenty (N = 120) students, sixty female (N = 60) and sixty (N = 60) male, age ranged between 12-19 years, who had passed O' level. The Reynolds Adolescents Adjustment Screening Inventory (RAASI) was used to measure psychological adjustment. Statistical Package for Social Sciences Version-20 (SPSS-20) was used for statistical analysis. First of all reliability of the scale was determined. Pearson Product Moment Correlation and Independent Sample T-Test were applied to find the quantitative facts of the study. Results revealed that there is negative correlation between psychological adjustment and academic achievement of students who passed O' level. Independent Sample t-test revealed that there is significant difference on psychological adjustment among students who passed O' level. The results also showed that female have more psychological adjustment as compared to male.