Background: Today, opioid use is recognized as a global concern, threatening people's physical and mental health. Objectives: This study was conducted to investigate the effects of self-control training on emotional wellbeing and opioid craving among men with opioid use disorder. Methods: In this quasi experimental study, the sample included all men with opioid use disorder, who were admitted to drug treatment centers of district 6, Tehran, Iran during year 2015. Fifty subjects were initially selected, matched, and randomly assigned to experimental and control groups (25 cases per group). After a diagnostic interview, the subjects were asked to complete the pretests, including the cognitive emotion regulation questionnaire (CERQ), facial expression recognition test (FERT), emotional processing scale (EPS), toronto alexithymia scale (TAS), and craving beliefs questionnaire (CBQ). The experimental group participated in 10 weekly sessions of self-control training. A week after the intervention, both groups were tested using the same instruments. For data analysis, multiple analysis of variance (MANOVA) test was applied in SPSS version 18. Results: Self-control training caused a significant increase in positive emotion regulation (P < 0.001), emotion recognition (P = 0.002), and emotion processing (P < 0.001), while reducing negative emotion regulation (P = 0.002), alexithymia (P < 0.001), and opioid craving in men with opioid use disorder (P < 0.001). Conclusions: Self-control training exerts a significant effect on the improvement of emotional wellbeing in men with opioid use disorder and reduces their opioid craving.