This study explores the monitoring process longitudinally among a sample of rural early adolescents and addresses two research questions: (a) Does maternal knowledge mediate the relationship between three aspects of the parental monitoring process and adolescent problem behavior: active parent monitoring efforts, youth disclosure, and parental supervision? (b) Are these meditational pathways moderated by the affective quality of the parent–child relationship? Parent efforts to monitor youth and youth disclosure in the Fall of Grade 6 predicted substance use and delinquency in Grade 8. These relations were mediated by increases in maternal knowledge assessed in the Spring of Grade 6, suggesting that the protective effects of these constructs are partially indirect. Supervision was not significantly related to maternal knowledge or problem behavior. Parent efforts to monitor were more strongly related to maternal knowledge in families with high levels of positive affect than in families with low levels of positive affect.