Moderation and mediation models of the relation between religiosity and effortful control as predictors of problem behavior and aggression were assessed in this study of 237 16-year-old Muslim Indonesian adolescents. Adolescents reported their engagement in behavior required and recommended by their religion and their effortful control using the Early Adolescent Temperament Scale. Adolescents self-reported their problem behavior and peers nominated aggressive classmates. Religiosity moderated the relation between effortful control and both types of antisocial behavior. The relations between religiosity and problem behavior and peer nominated aggression were respectively partially and fully mediated by effortful control. Using Bayesian information criteria, the moderation models were superior to the mediation models. The present findings extend findings pertaining to the interconnection between effortful control and religiosity as predictors of antisocial behavior to a Muslim population. (PsycINFO Database Record (c) 2019 APA, all rights reserved)