This multicenter randomized controlled trial investigated whether interactive virtual reality enhanced effectiveness of Cognitive Behavioral Therapy (CBT) to reduce children's aggressive behavior problems. Boys with aggressive behavior problems (N = 115; M[subscript age] = 10.58, SD = 1.48; 95.7% born in Netherlands) were randomized into three groups: CBT with virtual reality, CBT with roleplays, or care-as-usual. Bayesian analyses showed that CBT with virtual reality more likely reduced aggressive behavior compared to care-as-usual for six of seven outcomes (ds 0.19-0.95), and compared to CBT with roleplays for four outcomes (ds 0.14-0.68). Moreover, compared to roleplays, virtual reality more likely enhanced children's emotional engagement, practice immersion, and treatment appreciation. Thus, virtual reality may be a promising tool to enhance CBT effectiveness for children with aggressive behavior problems.