Grounded in theories and empirical research, the present study examined the mediating processes of emotion dysregulation and teaching self-efficacy between mindfulness and depressive symptoms among preservice teachers in China. A total of 288 preservice teachers ranging from 18 to 40 years old (men = 94; women = 194) completed an online self-report questionnaire. Path analysis revealed that emotion dysregulation mediated the relation between mindfulness facets, including acting with awareness and nonjudging to inner experience, and depressive symptoms among Chinese preservice teachers. In addition, mindfulness facets including observing, describing, and nonreacting to inner experience were positively related to teaching self-efficacy among preservice teachers. However, teaching self-efficacy was not significantly associated with depressive symptoms. These findings underscore the potential importance of preservice teachers' emotion dysregulation as a process between mindfulness and depressive symptoms, as well as the role of mindfulness in enhancing teachers' teaching self-efficacy.