The purpose of this study is to examine the impact of positive psychotherapy on decreasing the students' stress, anxiety, depression and increasing their well-being. In this study, an experimental research method was adopted using a pretest-posttest control group design. A total of 34 undergraduate students were sampled out of 1200 students in academic year 2013-2014 University of Shahid Beheshti. Using convenience sampling, the participants were randomly assigned to the experimental and control groups. The instruments employed in the study included Depression/ Anxiety and Stress Scale Lovibond (1995) and positive psychotherapy inventory (Rashid & Seligman, 2013). The positive psychotherapy was trained to the experimental group on a weekly basis during six two-hour sessions. The results of covariance indicated that positive psychotherapy was effective in decreasing stress, anxiety, depression and increasing the students' well-being and that their permanence was observed two months after the experiment. Because the early period of the students' life is stressful, and as the results represented, positive psychotherapy can be beneficial for students as an effective way to strengthen the psychological resources and mental health.
