PurposeThis study assessed whether the combined effect of parental control/support and peer delinquency on future participant offending was cumulative, interactive, or redundant. MethodsA review of database studies available through the Inter-university Consortium for Political and Social Research (ICPSR) website identified 10 longitudinal studies with prospective self-report data on parental control/support, peer delinquency or deviance, and future offending in participants 18 years of age and younger. ResultsA multiple group analysis revealed that while there was mild to moderate evidence of measurement invariance or consistency of results across gender and race, there was no evidence of consistency of substantive relationships across the 10 studies. A review of findings from each individual study revealed that while the parent and peer main effects were each significant in 9 out of the 10 studies, the parent x peer interaction was significant in only 1 out of 10 studies. ConclusionsThe fact that the parent and peer main effects achieved combined significance in 8 out of 10 studies, while their interaction achieved significance in only one study, suggests that the relationship between parenting and peers is more cumulative than interactive. These results have important implications for theory, research, and practice.