Recent studies suggest that most of what parents know about their adolescent offspring’s whereabouts and companions is the result of youth disclosure, rather than information gained through active parental monitoring. This raises the possibility that parental knowledge is spuriously correlated with youth delinquency solely because the most delinquent youth disclose the least information to parents (because they have the most to hide). We tested this spurious association hypothesis using prospective data on offspring of a nationally representative sample of US women, controlling demographic and contextual covariates. In separate analyses, greater parental knowledge of their offspring’s peer associations at both 12–13 years and at 14–15 years was associated with lower odds of being in the top 1 standard deviation of youth-reported delinquency at 16–17 years, controlling for delinquency at the earlier ages. The extent to which parents set limits on activities with peers at 14–15 years did not mediate or moderate the association between parental knowledge and delinquency, but it did independently predict future delinquency among adolescents living in high-risk neighborhoods. This suggests that the association between parental knowledge and future delinquency is not solely spurious; rather parental knowledge and limit setting are both meaningful predictors of future delinquency.