Background: The rise in marital violence has led to growing concern about people with this condition. Emotion-focused Therapy (EFT) is one of the well-established treatments that consider both family interaction and emotion in the creation of secure attachment. Objectives: This study aimed to evaluate the effectiveness of EFT in marital violence reduction and family functioning improvement. Methods: This study was conducted in 2018-2019 among married women with family problems referring to counseling centers in Tehran, Iran. We randomly allocated 32 women with a mean marriage age of 24.27 ± 6.18 years to EFT and control groups. Marital violence and family functioning were measured before and after EFT using a domestic violence questionnaire and the family assessment device scale constructed based on the McMaster Model of Family Functioning (MMFF). Emotion-focused group therapy was conducted in the intervention group for eight 90-min sessions. The control group was exposed to no intervention. The Kolmogorov-Smirnov test was utilized to evaluate the distribution of variables. We used the independent t-test, chi-square test, Friedman test, Mann-Whitney test, ANOVA, ANCOVA, and MANCOVA for data analysis. Results: Marital violence decreased significantly after the intervention (-11.25 vs.-1.62, P < 0.001). Moreover, family functioning improved after the intervention (6.25 vs.-1.69, P = 0.001) in the EFT group compared to the control group. Conclusions: The EFT was an effective intervention in this study. The findings implicate the significance of essential interventions for marital violence reduction and family functioning improvement.