This study examined the longitudinal consistency of mother-child reporting discrepancies of parental monitoring and whether these discrepancies predict children's delinquent behaviors 2 years later. Participants included 335 mother/female-caregiver and child (46% boys, >90% African American; age range 9-16 years [M = 12.11, SD = 1.60]) dyads living in moderate-to-high violence areas. Mother-child discrepancies were internally consistent within multiple assessment points and across measures through a 2-year follow-up assessment. Further, mothers who at baseline consistently reported higher levels of parental monitoring relative to their child had children who reported greater levels of delinquent behaviors 2 years later, relative to mother-child dyads that did not evidence consistent discrepancies. This finding could not be accounted for by baseline levels of the child's delinquency, maternal and child emotional distress, or child demographic characteristics. This finding was not replicated when relying on the individual reports of parental monitoring to predict child delinquency, suggesting that mother-child reporting discrepancies provided information distinct from the absolute frequency of reports. Findings suggest that mother-child discrepancies in reports of parental monitoring can be employed as new individual differences measurements in developmental psychopathology research.