Household and school-based surveys of self-reported drug use have revealed that marijuana use is fairly widespread. These surveys probably underestimate the prevalence of marijuana use. However, the widespread use of marijuana is consistent with evidence that marijuana use is generally perceived as being socially acceptable; widespread use persists despite evidence that frequent, prolonged use can have negative health consequences. Recent studies also indicate that heavy marijuana use during adolescence is associated with both involvement in crime and frequency of offending. This association is particularly evident for crimes such as breaking and entering, shoplifting, and motor vehicle theft. Little research exists regarding treatment effectiveness. However, a few random allocation studies with adult samples have suggest that cognitive-behavioral, social support, and psychotherapeutic or counseling-based interventions are promising treatments. These treatments appear to increase marijuana abstinence rates and to reduce the frequency of marijuana use. Evaluations of prevention programs that specifically target adolescents also suggest that the initiation of marijuana use and the progression to heavier marijuana use can be delayed, if not prevented. Thus, growing evidence indicates that both treatment and prevention programs for marijuana use may act as promising juvenile delinquency control strategies. Notes, appended discussion of unfinished studies involving random allocation, and 52 references