This study aimed to examine the effects of child maltreatment subtypes (physical abuse, sexual abuse, neglect, and exposure to domestic violence) and cumulative child maltreatment on depressive symptoms in adulthood, and examine the protective effects of social connectedness in a sample of formerly institutionalized females. The sample consisted of 124 females who were institutionalized in a Dutch juvenile justice institution during adolescence and were followed-up when they were on average 32 years old. Information about child maltreatment was extracted from treatment files. Retrospective data on social connectedness in young adulthood were established during interviews using a Life History Calendar. Relationship quality at follow-up was assessed with items derived from the Rochester Youth Development Study. The Center for Epidemiological Studies Scale for Depression (CES-D) was used to measure depressive symptoms in adulthood. Results showed that 85.5% of the females experienced child maltreatment, and co-occurrence of subtypes was high. Cumulative child maltreatment increased the risk of depression in adulthood. Furthermore, social connectedness, that is, more employment over time and the quality of the romantic relationship at follow-up, protected against the development of depression. However, social connectedness did not buffer the effect of maltreatment on depression. Our findings indicate that treatment of these girls should focus on improving the social-emotional development to promote positive interpersonal relationships and include educational and vocational components to guide these girls toward increased opportunities on the labor market.