There have been impressive, recent advances in the development of efficacious treatments for child and adolescent behavior problems. However, specific methods for delivering these treatments in a way that amplifies their efficacy have not been well articulated. Although many factors may be involved, attendance and adherence to treatment are arguably the most basic necessities for effective treatment delivery. We provide a conceptual and empirical review of past research on attendance and adherence to child and adolescent therapy, with a special focus on the importance of parents/guardians in managing treatment participation. Our review demonstrates that attendance and adherence are associated with a range of significant methodological, clinical, and financial outcomes. Several pretreatment predictors of attendance and adherence have been identified; however, to date only 12 controlled, clinical trials have evaluated strategies for enhancing attendance and adherence to child therapy. We conclude with an agenda for advancing research on the prediction and enhancement of attendance and adherence to child therapy as a means of improving the efficiency and effectiveness of child treatments.