Social anxiety has been the focus of clinical attention as a common problem in the realm of childhood, adolescence and adulthood, due to various problems in compatibility and performance of patients and comorbidity with many adult disorders such as anxiety, depression and avoidant personality disorder. Therefore several treatment models are designed for the restoration of this disorder. One of these models is mindfulness training. Accordingly, the aim of this study was to determine the effectiveness of mindfulness-based stress reduction (MBSR) on reducing symptoms of social anxiety from a sample of Iranian girl students who were diagnosed. Accordingly, 21 subjects with social anxiety disorder based on the Social Phobia Inventory (SPIN) and the Structured Clinical Interview based on the Diagnostic and Statistical Manual of Mental Disorders (SCID-I) were selected and 10 in the experimental group and 11 patients in group Control were replaced. The experimental group received eight sessions of mindfulness-based stress reduction (MBSR) and the control group remained on hold. The subjects were completed Social Phobia Inventory (SPIN) before and after treatment. Data analysis was performed by comparing mean scores of pre-test - post-test, according to U Man-Whitney test. The results have shown that mindfulness-based stress reduction program led to a reduction in social anxiety symptoms of fear, avoidance, and psychological distress in patients. Based on the findings of this research, mindfulness program has been effective in reducing the symptoms of social anxiety disorder and other parameters in spite of belonging to different culture. So it seems that with regards to the limitations of current research and observance of clinical precautions, this program can be used in treatment centers for samples with social anxiety.