Background &objectives: Nowadays, paying special attention to the university students has a paramount importance; as well as their psychological health. The initial schema is the factors that disturb the quality of life. Therefore, this study aimed to determine the effectiveness of group schema therapy on psychological well-being and aggression among university students.

Methods: The research was a semi-experimental study with pretest-posttest control group design. The study population was included all male students of Applied Sciences and Technology University of Kermanshah in the year of 2014. Of the students with lowest scores in the scale of Psychological Well-being Questionnaire (RSPWB) and has earned the highest scores in the Buss-Perry Aggression Questionnaire (AQ), 40 students were selected randomly into the experimental (N=20) and the control (N=20) groups. The experimental group participated in the eleven 60-min educational intervention (Schema Therapy). After treatment, both groups completed Psychological well-being Questionnaire and Aggression Questionnaire. The data were analyzed using ANCOVA test.

Results: The results showed that schema therapy in the experimental group increased the average well-being components and reduced components of aggression in the post-test scores, but there was no such change in the control group, the difference in the two group was significant (p<0.001).

Conclusion: According to the effectiveness of schema therapy in improving psychological well-being and decreasing aggression in students, it can be used as an effective therapy for reducing aggression and improving mental health of this group in the society.