We investigated the influence of the child's behavior on the quality of the mutual parent-child attachment relationships across three generations. We did so using a prospective longitudinal study which spanned 20 years from adolescence through adulthood. Study participants completed in-class questionnaires as students in the East Harlem area of New York City at the first wave and provided follow-up data at 4 additional points in time. 390 participants were included in these analyses; 59% female, 45% African American, and 55% Puerto Rican. Using structural equation modeling, we determined that externalizing behavior in the child was negatively related to the mutual parent-child attachment relationship for two generations of children. We also found continuity in externalizing behavior for the participant over time and from the participant to his/her child. Additionally, we found continuity in the quality of the mutual attachment relationship from the participant's relationship with his/her parents to the participant's relationship with his/her child. Finally, the mutual attachment relationship of the participant with his/her parents had a negative association with the participant's externalizing behavior in adulthood. Based on these results, we propose that family interventions should focus on the role of the child's externalizing behavior in the context of the parent-child attachment relationship. Furthermore, we suggest that prevention programs should address externalizing behavior as early as possible, as the effects of externalizing behavior in adolescence can persist into adulthood and extend to the next generation.