Objective: To assess the efficacy of trauma-focused cognitive behavioral therapy (TF-CBT) delivered by nonclinical facilitators in reducing posttraumatic stress, depression, and anxiety and conduct problems and increasing prosocial behavior in a group of war-affected, sexually exploited girls in a single-blind, parallel-design, randomized, controlled trial. Method: Fifty-two 12- to 17-year-old, war-affected girls exposed to rape and inappropriate sexual touch in the Democratic Republic of Congo were screened for trauma, depression and anxiety, conduct problems, and prosocial behavior. They were then randomized to a 15 session, group-based, culturally modified TF-CBT (n = 24) group or a wait-list control group (n = 28). Primary analysis, by intention-to-treat, involving all randomly assigned participants occurred at pre- and postintervention and at 3-month follow-up (intervention group only). Results: Compared to the wait list control, the TF-CBT group experienced significantly greater reductions in trauma symptoms (F[subscript 1.49] = 52.708, p less than 0.001, X[subscript p][superscript 2] = 0.518). In addition, the TF-CBT group showed a highly significant improvement in symptoms of depression and anxiety, conduct problems, and prosocial behavior. At 3-months follow-up the effect size (Cohen's d) for the TF-CBT group was 2.04 (trauma symptoms), 2.45 (depression and anxiety), 0.95 (conduct problems), and -1.57 (prosocial behavior). Conclusions: A group-based, culturally modified, TF-CBT intervention delivered by nonclinically trained Congolese facilitators resulted in a large, statistically significant reduction in posttraumatic stress symptoms and psychosocial difficulties among war-affected girls exposed to rape or sexual violence. Clinical trial registration information--An RCT of TF-CBT with sexually-exploited, war-affected girls in the DRC; http://clinicaltrials.gov/; NCT01483261. (Contains 1 figure and 6 tables.)