The concurrent and predictive influence of deviant peers on boys' disruptive and delinquent behavior was examined in a community sample of fourth- and seventh-grade boys, who were followed-up over six data waves. Analyses were conducted separately for three different types of behavior problems: authority conflict, covert, and overt disruptive behavior. Consistent with the existing literature, concurrent relations between peers' and boys' disruptive behavior were expected to be significant. A more informative test, however, was whether exposure to deviant peers resulted in boys' subsequent initiation of disruptive behavior. Although peer influences were expected in the predictive analyses, the relations were hypothesized to differ by type of behavior. The potential moderating effects of hyperactivity and poor parenting practices were also examined to test the hypothesis that boys who are already at risk for behavior problems will be more susceptible to deviant peer influence. Results supported the significant concurrent and predictive relation between exposure to deviant peers and boys' engagement in disruptive and delinquent behavior. There were no significant moderating effects of attention-deficit hyperactivity disorder (ADHD) or parenting practices on peer influence.