Evidence-based treatments exist for a range of child and adolescent behavior problems; however, effects are often limited by poor treatment attendance and adherence. The authors developed and evaluated the efficacy of a brief (5 to 45 min) intervention designed to increase treatment attendance and adherence in a sample of 76 parents referred for treatment of their child's oppositional, aggressive, and antisocial behavior. The results of this randomized controlled trial showed that parents who received this brief intervention had greater treatment motivation, attended significantly more treatment sessions, and had greater adherence to treatment according to both parent and therapist report. This study provides researchers and clinicians with a brief and efficacious method of increasing motivation, attendance, and adherence for treatment.