This study examined the impact of a parenting intervention on child development, parenting ability, and family functioning in a trauma-informed residential substance abuse treatment program for women and their children. Recent research supports the inclusion of parenting interventions in residential treatment with this population of women, yet questions remain regarding what outcomes emerge as a result of these interventions. Factors associated with child development, parenting ability, and family functioning such as cumulative risks, abuse history, and severity of substance abuse were examined at intake, as were changes over time in these domains for program completers and non-completers. Data were obtained on 82 women and 107 children enrolled in an implementation of a multi-site study funded by the Substance Abuse and Mental Health Services Administration. With respect to improved parenting ability and family functioning, results from this study suggest that women gained from being engaged in treatment regardless of whether they successfully completed the treatment program or left prematurely. A woman's abuse history accounted for deficits in family functioning upon entry into treatment; however, women with and without an abuse history were equally helped by treatment. Qualitative analysis of the participants' responses indicated that learning healthy parent characteristics such as patience, appropriate boundaries, and relationship consistency were the most helpful aspects of the parenting intervention. Implications for practice, policy, and research are discussed.