Tehran University of Medical Sciences Iranian Journal of Psychiatry 1735-4587 11 4 2016 12 31 206 213 EN Hamed Ghiasi PhD Student in Clinical Psychology, Shahid Beheshti University of Medical Sciences, Tehran, Iran. Abolalfazl Mohammadi Assistant Professor of Clinical Psychology, Department of Psychiatry, Tehran University of Medical Sciences, Roozbeh Hospital,Tehran, Iran. Pouria Zarrinfar MA in Clinical Psychology, Islamic Azad University, Science and Research Branch, Tehran, Iran. 2016 12 03 Objective: Borderline personality disorder is one of the most complex and prevalent personality disorders. Many variables have so far been studied in relation to this disorder. This study aimed to investigate the role of emotion regulation, attachment styles, and theory of mind in predicting the traits of borderline personality disorder. Method: In this study, 85 patients with borderline personality disorder were selected using convenience sampling method. To measure the desired variables, the questionnaires of Gross emotion regulation, Collins and Read attachment styles, and Baron Cohen's Reading Mind from Eyes Test were applied. The data were analyzed using multivariate stepwise regression technique. Results: Emotion regulation, attachment styles, and theory of mind predicted 41.2% of the variance criterion altogether; among which, the shares of emotion regulation, attachment styles and theory of mind to the distribution of the traits of borderline personality disorder were 27.5%, 9.8%, and 3.9%, respectively.‎‎ Conclusion: The results of the study revealed that emotion regulation, attachment styles, and theory of mind are important variables in predicting the traits of borderline personality disorder and that these variables can be well applied for both the treatment and identification of this disorder. https://ijps.tums.ac.ir/index.php/ijps/article/view/883 https://ijps.tums.ac.ir/index.php/ijps/article/download/883/580