Although the relationships between depressive symptoms and harm avoidance, locus of control, and repetitive thinking have been studied in many studies, there is no research including these variables together in the literature. In this study, a moderated mediation model proposed by Hayes (2013) was tested to examine the mediating effect of repetitive thinking between harm avoidance and depressive symptoms, and to examine the moderating effect of the locus of control on this mediation model. The sample consists of 359 university students in Ege University. Temperament Character Inventory-Harm Avoidance Subscale, Repetitive Thinking Questionnaire, Locus of Control Scale, Beck Depression Inventory were used as data collection tools. According to the results, repetitive thinking had a partial mediating effect on the relationships between harm avoidance and depressive symptoms. Moreover, locus of control had a moderating effect on the relationship between harm avoidance and depressive symptoms which was mediated by repetitive thinking. It has been found that this mediation is stronger as the external locus of control increases. While supporting the importance of cognitive behavioral therapy in reducing depressive symptoms, these findings emphasize that rumination-focused techniques may also contribute to the treatment.