Delinquency and substance use are more likely to co‐occur in adolescence compared to earlier and later developmental periods. The present study examined developmental pathways to co‐occurring problem behavior from 6th to 10th grade (N = 2,002), testing how peer delinquency and substance use were linked to transitioning between abstaining, delinquency, substance use, and co‐occurring problem behavior. Developmentally, most youth transition from abstinence to delinquent behavior and then escalate to co‐occurring problem behavior. Once co‐occurring problem behavior onsets, remitting to single‐problem behavior or abstinence is unlikely. The impact of peers on problem behavior is domain‐specific when individuals transition from abstaining to a single‐problem behavior, but is more general with respect to escalation of and desistance from problem behavior.