Child maltreatment contributes to depression in adults. Evidence indicates that such experiences are associated with poorer outcomes in treatment. Mothers in home visiting programs display high rates of depression and child maltreatment histories. In-Home Cognitive Behavioral Therapy (IH-CBT) was developed to treat maternal depression in home visiting. The purpose of this study was to examine the moderating effects of child maltreatment history on depression, social functioning, and parenting in mothers participating in a clinical trial of IH-CBT. Ninety-three depressed mothers in home visiting between 2 and 10 months postpartum were randomly assigned to IH-CBT (n = 47) plus home visiting or standard home visiting (SHV; n = 46). Mothers were identified via screening and then confirmation of major depressive disorder diagnosis. Measures of child maltreatment history, depression, social functioning, and parenting were administered at pre-treatment, post-treatment, and 3-month follow-up. Results indicated high rates of maltreatment in both conditions relative to the general population. Mixed model analyses found a number of main effects in which experiences of different types of trauma were associated with poorer functioning regardless of treatment condition. Evidence of a moderating effect of maltreatment on treatment outcomes was found for physical abuse and parenting and emotional abuse and social network size. Future research should focus on increasing the effectiveness of IH-CBT with depressed mothers who have experienced child maltreatment.