Objective Systematically review and meta-analyze the pediatric literature on behavior-change techniques (BCT) as defined by Abraham & Michie (Health Psychology, 27, 379-387, 2008), and describe whether the most effective BCTs are incorporated in physical activity (PA) and dietary mobile apps. Methods Randomized controlled trials (n = 74) targeting diet or PA were meta-analyzed. Metaregressions were used to determine which BCTs predict aggregate effect size (ES). iTunes (TM) apps were coded for presence/absence of BCTs that produce larger ES. Results Modeling was the only predictor of PA ES in children (aged 6-13 years). Consequences for behavior, other's approval, self-monitoring, intention formation, and behavioral contracting significantly predicted PA for adolescents. Modeling and social support predicted dietary ES in adolescents and children, respectively. Practice was also a significant predictor for children. A majority of effective strategies for children were not widely incorporated in apps; however, the picture is more optimistic for adolescents. Conclusions More collaboration is needed between pediatric psychologists and technologists to incorporate evidence-based BCTs into developmentally appropriate mobile apps.