Objective: The present study examined the effect of a conflict resolution teaching program on the social competencies of children with attention-deficit/hyperactivity disorder (ADHD). Method: In this controlled quasi-experimental study with a pretest-posttest design and follow up, a sample of 21 students with ADHD was selected from among students of the 5^th and 6^th grades of elementary schools (11 and 12 years of age) in Tehran, Iran, through multistage random sampling and then randomly assigned to experimental and control groups. Child Symptom Inventory-4 (CSI-4, parent checklist) and Felner’s Social Competence Inventory were used for the diagnosis of ADHD and assessment of social competencies, respectively. A conflict resolution program was implemented for the experimental group for 12 sessions (60 minutes each, twice a week). Results: Variance Analysis showed a significant difference in social competency and its components (cognitive, behavioral, emotional, and motivational) between the experimental and control groups. Conclusion: Research findings showed that the conflict resolution program increases the social competencies of children with ADHD.