Objective High-risk behaviors are seriously threatening health and wellbeing, and increasing the likelihood of physical, psychological, and social consequences. High-risk behaviors, such as tobacco use, drug abuse, alcohol use, or malicious behaviors can endanger the health and wellbeing of adolescents and hinder their success and future growth. Today, the prevalence of high-risk behaviors among adolescents has become one of the most important concerns in society and despite the provisions made in recent years, its rate has increased. One of the vulnerable groups is orphaned/abandoned adolescents who face various social and psychological problems during their stay in welfare bearding centers that requires special skills to deal with. This study aimed to investigate the effect of social competence training on the tendency towards high-risk behaviors in male adolescents living in welfare boarding centers. Materials & Methods This is a quasi-experimental study with a pre-test-post-test design. The study population included all male adolescents aged 12-18 years living in welfare boarding centers located in Sabzevar and Mashhad cities in Iran. For sampling, 15 adolescents were selected from a boarding center in Sabzevar City by census method and assigned to the experimental group, and 15 from a boarding center in Mashhad City selected randomly and assigned as controls. The experimental group received social competence training program in twelve 60-min sessions, while the control group received only two 8-hour first aid training. Iranian Adolescents Risk-Taking Scale (IARS) and a demographic form were used to collect data before and after the intervention. The collected data were analyzed by Multivariate Covariance Analysis (MANOVA) in SPSS V. 22. Results The mean IARS scores in the experimental group decreased from 93.9 to 86.81 after the intervention, and the t test results indicated a significant difference between the mean scores before and after the intervention (t=2.97, P=0.010). The MANCOVA results revealed a significant difference between the mean overall score of IARS (F=24.08, P<0.001), and between the mean scores of IARS dimensions (tendency towards dangerous driving, violence, smoking, drug abuse, alcohol use, sexual activity and behavior, and relationship with the opposite gender) in the experimental and control groups after the intervention (P<0.001). Based on Eta squared values, 47.1% of changes in the tendency towards high-risk behaviors in subjects can be explained by the social competence training program. Therefore, social competence training had a positive effect on reducing the tendency towards risky behaviors among male adolescents living in welfare boarding centers. Conclusion The social competence training program could improve the skills and adaptive capacity of orphaned/abandoned adolescents in different situations to deal with their problems. Therefore, it is recommended that social competence training programs be provided for male adolescents living in boarding schools to effectively increas...