Behavioral parent training is an efficacious treatment for attention-deficit/hyperactivity disorder (ADHD). However, single-mother households are at high risk for poor outcomes during and following behavioral parent training. This study randomly assigned cohorts of 120 single mothers of children (ages 5-12 years) with ADHD to a waitlist control group, a traditional behavioral parent training program, or an enhanced behavioral parent training program -- the Strategies to Enhance Positive Parenting (STEPP) program. Intent-to-treat analysis demonstrated benefits of participating in behavioral parent training, in general, and the STEPP program more specifically at immediate posttreatment on child and parental functioning. Moreover, the STEPP program resulted in increased engagement to treatment. However, results indicated that behavioral parent training does not normalize behavior for most children and treatment gains are not maintained.