Objective: The present study evaluated the model of mediating variables concerning effectiveness of mindfulness in improving women's marital satisfaction. Method: This study was quasi-experimental with pre-test, post-test and control groups. The statistical population included every married woman in Tehran in the year 1396 (2017). The research sample was composed of 60 married women with moderate marital satisfaction. They were chosen using the convenient sampling technique and were randomly assigned to control and experimental groups. The experimental group attended 8 sessions of Mindfulness-Based Stress Reduction (MBSR) and the control group was on a waiting list. Both groups answered the Five Facet Mindfulness Questionnaire (FFMQ), the Depression, Anxiety, and Stress Scale (DASS), Difficulties in Emotion Regulation Scale (DERS), Interpersonal Reactivity Inventory (IRI), Needs for Intimacy Questionnaire of Bagarozi, Positive and Negative Affect Scale (PANAS) and the Couple Satisfaction Index (CSI) before and at end of intervention. The data were analyzed by Structural Equation Modeling (SEM) using PLS-22 and SPSS-23. Results: In the initial hypothetical model, which included the direct effect of mindfulness on marital satisfaction and its indirect effects through psychological distress, emotion regulation, empathy, marital intimacy and positive emotion on marital satisfaction, coefficients of all model paths were significant at 95% level except direct path of mindfulness to marital satisfaction (t = 1.14), marital intimacy to marital satisfaction (t = 0.48) and positive affection to marital satisfaction (t = 1.75). After removing the non-significant paths, the model was tested again and the model fit index (GOF = 0.47) was a very good fit for the modified overall model. Conclusion: The results identified mindfulness-based stress reduction intervention was effective in enhancing marital satisfaction through reducing psychological distress and improving emotion regulation and empathy.