The purpose of this study was to predict depression in college students based on assertiveness skills and attachment styles. The current research was descriptive and correlational.  In this study, 100 students were selected by available sampling method and they were given questionnaires of personal information, assertiveness skills of Gambrill and Richey (1975), attachment styles of Collins and Read (1990) and depression of Beck (1961). The data was analyzed in SPSS-27 statistical software. Correlation and regression analysis methods were used to analyze the relationship between variables. The results showed that there is a significant negative relationship between the assertiveness skills of students and depression, so that with the increase of each, the other decreases. Also, there is a negative and significant relationship between secure and insecure avoidant attachment style with depression, and there is a positive and significant relationship between ambivalent insecure attachment style and depression, and only secure attachment and ambivalent insecure attachment predict depression. According to the results, it can be concluded that increasing assertiveness skills in people can help mental health and reduce depression. Also, the attachment style formed during infancy and childhood has a significant effect on suffering from disorders in adulthood, especially depression.