Three variables were tested as moderators of the relationship between peer deviancy training and child antisocial behavior in a longitudinal study of 267 boys and girls from ages 5.3 to 9.3 years. Deviancy training was directly measured by observation of the discourse and play of children with same-gender classmates. Peer deviancy training was significantly related to multi-setting child antisocial behavior from ages 5.3 to 9.3 years. Child impulsivity, poor parental discipline, and peer rejection were all significant moderators of that relationship, even in the context of their direct association with trajectories of antisocial behavior and after controlling for deviant peer affiliation. These moderator effects appeared to be associated with children's increased sensitivity to peer modeling and reinforcement of deviant discourse and play. Not all children are equally affected by peer deviancy training, and an array of intervention strategies are described that may serve to protect children from deviant peer influence. (Contains 4 figures and 2 tables.)