The present study was conducted to predicting marital jealousy based on self-differentiation components and attachment styles. This is a descriptive correlational study. The statistical population of this study is all married people in 2nd and 5th areas of Tehran in 2020, That 200 of them were selected by available sampling method and they completed the Multidimensional Scale of Marital Jealousy (Pfeiffer & Wong, 1989), Revised Adult Attachment Scale (Collins & Reid, 1990), and Self-Differentiation Questionnaire (Skowron & Friedlander, 1998). The data were analyzed by Pearson Correlation and Regression Analysis. The results of this study showed that the Marital Jealousy have a negative relationship with Secure Attachment, and have a positive relationship with Avoidance and Anxiety Attachment. In Self-Differentiation levels, I position was positively associated with Marital Jealousy, and three other dimensions, namely Emotional Reactivity, Fusion with others, and Emotional Cutoff, were negatively associated with Marital Jealousy. Among Attachment Styles, Anxiety Attachment Style is a significant predictive for the cognitive dimension of Marital Jealousy. It can be concluded that the Marital Jealousy is predictable by the dimensions of Attachment and Self-Differentiation. Therefore, by improving Self-Differentiation and Attachment Styles, can be reduced negative effects of Marital Jealousy in Couples.