Objective: The aim of this study was to compare the effectiveness of Barlow's transdiagnostic, emotion-focused and mindfulness therapy on moderating the eating behavior of adults with obesity. Method: The present research project was a quasi experimental pre test- post test, and follow up with a control group. The statistical population included all people with obesity in Tehran. Sixty people were randomly selected through available sampling methods and were assigned to four groups: (1) Barlow's transdiagnostic therapy, (2) emotion- focused therapy, (3) mindfulness-based therapy and (4) control group. Data were analyzed using the Dutch Eating Behavior Questionnaire (DEBQ) in three stages: pre test,- post test, and follow up, and were analyzed by mixed-design analysis of variance test. Results: The research findings showed that intragroup effects regarding emotional, environmental, and inhibited eating were significant (p <0.05). Regarding intergroup effects, a significant and stable effectiveness was found in the subscale of emotional and inhibited eating in emotion- focused therapy group and in the subscale of environmental eating in mindfulness-based therapy group (p <0.05). Conclusion: Based on the results of this study, it can be said that emotion- focused therapy, can help people to moderate emotional and inhibited eating through emotional experience and making sense of emotions, and mindfulness therapy can help people to moderate environmental eating by making them focus on the present moment and break repetitive patterns.