This study examined the moderating role of sociotropy on the association between the cumulative effect of multiple adverse childhood experiences (ACEs), namely parental loss before 15 years and household psychopathology prior to 18 years (substance abuse; mental illness; familial suicide), on depressive symptom severity following brief treatment for Major Depressive Disorder (MDD). This study also investigated the mediating effects of the patients' perceived quality of the therapeutic relationship on the hypothesized moderating model. This study utilized archival public data from the Treatment of Depression Collaborative Research Program (TDCRP). The sample of the study consisted of 162 male and female outpatients between the ages of 21 and 60 years who met Research Diagnostic Criteria (RDC) for a current episode of MDD who completed at least 12 weeks of treatment. The results revealed that of the 112 participants endorsing ACEs, 17% endorsed parental loss and 90.2% endorsed household psychopathology. Of those reporting ACEs, 63.4% reported experiencing only one ACE, 31.3% reported two, 4.5% reported three, and .9% reported the presence of all four ACEs. Results of multiple regression analyses did not support the hypothesis that participant sociotropy would significantly moderate the relationship between the total number of ACES reported and depressive symptom severity post-treatment. The endorsement of any ACE was shown to be associated with depression severity post-treatment on the BDI after controlling for depression severity at baseline and the presence of multiple ACEs and baseline depression severity were shown to significantly predict depression severity post-treatment. The findings are discussed in relation to their implications for counseling psychologists designing and implementing depression prevention programs for youth and adults and providing mental health services to depressed adults with psychosocial histories of ACEs. Suggestions for future research are also emphasized.