his study aimed to determine the efficacy of training collaborative interpersonal conflict resolution skills on social competence and emotional expressiveness in male students with signs of bullying. it was a quasi experimental study with a pretest, posttest, control group, and two month follow up period. the sample consisted of male students with signs of bullying in the first secondary school of yasouj in the academic year 2018 19. the research participants included 40 students with signs of bullying who were selected through a multi stage random sampling method and randomly accommodated into experimental and control groups (each group of 20 students) and completed the illinois bullying scale (espelage & holt, 2001), social competence questionnaire (felner, lease & philips, 1990), and emotional expression questionnaire (king & emmons, 1990). the pretest was administered to two groups before starting the intervention; afterward, the experimental group was under training in collaborative interpersonal conflict solution skills for nine weeks, although the control group did not receive any intervention. at the end of the intervention, both groups were taken the post test and the follow up test was too taken two months after the posttest. the results showed that training in collaborative interpersonal conflict resolution has a significant effect on social competence and emotional expressiveness in male students with signs of bullying. these effects continued at the follow up stage. the findings of the present study implied that training collaborative interpersonal conflict resolution skills can be used as an efficient method to improve social competence and emotional expressiveness in male students with the signs of bullying through employing techniques such as problem solving skill and choosing rational criteria and commitment to reach these criteria.