en ● International Health مقاله اصيل پژوهشي Orginal Article <strong>Background</strong>: The prevalence of self-injury behavior and negative emotions in adolescents is high. This study aimed to investigate the effect of emotional regulation group training on self-injury behavior, depression, and anger in adolescents.<br> <strong>Methods</strong>: The research method is quasi-experimental with a Pre-test-post-test design and a control group. The study population comprised adolescents aged 13-15 years living in Shiraz City, Iran, in 2020 with self-injury experience. A total of 30 samples were selected by multi-stage cluster random sampling method and randomly assigned to the two groups of experimental and control (each 15 members). A Pre-test evaluated members of both groups. Then emotion regulation group training was applied online to the experimental group. After that, the participants in both groups were assessed in the post-test. Data collection tools were deliberate self-harm inventory, Kutcher adolescent depression scale, and state and trait anger expression inventory. Descriptive Statistics (SD) and inferential statistics (multivariate covariance) were used to analyze the obtained data<br> <strong>Results</strong>: The results of the multivariate covariance test showed that group training of emotion regulation affected self-injury behavior, depression, and anger (P<0.05). Data analysis showed a significant difference between the experimental and control groups regarding self-injury, depression, and anger. Emotion-regulation group training reduced self-injury behavior and the rate of depression and anger in adolescents.<br> <strong>Conclusion</strong>: Emotion-regulation group training is one of the new therapies to reduce problems. This study also confirms its effectiveness on emotions and dysfunctional behaviors of adolescents.&nbsp; Group training, Emotion regulation, Self-injury, Depression, Anger, Adolescents 383 392 http://jrh.gmu.ac.ir/browse.php?a_code=A-10-1602-4&slc_lang=en&sid=1 Tayebeh Vafaei vafaei.tayebe@yahoo.com 3380654035 100319475328460022655 No Department of Educational Sciences, Faculty of Humanities, University of Hormozgan, Bandar Abbas, Iran. Seyyed Abdolvahab Samavi wahab.samavi@gmail.com 5159107053 100319475328460022656 Yes Department of Counseling, Higher Education, and Speech-Language Pathology, Faculty of Education, University of West Georgia, Carrollton, Georgia, USA. Julia L. Whisenhunt jwhisenh@westga.edu 5159107053 100319475328460022657 No Department of Counseling, Higher Education, and Speech-Language Pathology, Faculty of Education, University of West Georgia, Carrollton, Georgia, USA. Samaneh Najarpourian snajjarpourian@gmail.com 2571776381 100319475328460022658 No Department of Educational Sciences, Faculty of Humanities, University of Hormozgan, Bandar Abbas, Iran.