The current study tested whether an abbreviated version of Defiant Children (Barkley, 1987), an efficacious parent training program to address the behavioral noncompliance often associated with disruptive behavior disorders, could be implemented successfully within a community mental health clinic setting by master's-level therapists. Ethnically and socioeconomically diverse parents of 16 children (ages 4 to 12 years old) completed a 6-session active treatment group emphasizing the use of differential attending skills, effective time-out strategies, and a structured reinforcement schedule to increase child compliance. Pre- and posttreatment measures of attention-deficit/hyperactivity disorder (ADHD), oppositional-defiant disorder (ODD), and conduct disorder (CD) symptom level were administered, as well as a measure tapping the contextual breadth (i.e., number of settings) and severity of disruptive behaviors. Parent satisfaction with the treatment was also assessed. Analyses indicated large treatment effects on all measures except CD behavior. Results are discussed in the context of implementing empirically supported therapies in settings where “treatment as usual” is the norm.