The effectiveness of metacognitive therapy in modifying inflated responsibility beliefs to reduce symptoms of obsessive-compulsive disorder among postgraduate students. Abstract: This research aimed to recognize the effectiveness of metacognitive therapy in modifying inflated responsibility beliefs to reduce the symptoms of obsessive-compulsive disorder among postgraduate students. The sample consisted of (16) postgraduate students at the Faculty of Education, Zagazig University, divided into two groups, each group consisted of (8) students (7 females, 1 male) aged ranged (21: 38) years (M=24.46, SD=2.97), They completed the obsessive symptoms scale and the inflated responsibility beliefs scale, the results showed that there were statistically significant differences at the level of (0.05) between the mean of ranks of the experimental and the control groups in the post-test on the inflated responsibility beliefs scale and the obsessive symptoms scale in favor of the post-test of the experimental group, and there were statistically significant differences at the level of (0.05) between the mean of ranks of the experimental group members in the pre and post-test on the inflated responsibility beliefs scale and the obsessive symptoms scale in favor of the post-test in the best direction, While there were no statistically significant differences between the mean of ranks of the experimental group members in the post- and follow-up test on the two scales. Conclusion: Metacognitive therapy is effective in modifying inflated responsibility beliefs and reducing symptoms of obsessive-compulsive disorder. The results were discussed, and some recommendations were presented in the light of them. Keywords: Metacognitive Therapy, Obsessive-compulsive disorder, Inflated responsibility beliefs, Postgraduate students.