There is a growing consensus that aggressive behaviors are elicited and promoted by the reciprocity between parents and children. Control systems theory (Bell, 1977) argues that children's genetically driven predispositions elicit negative parenting which in turn promotes children's aggressive behavior, while coercion theory (Patterson, 1982) argues that inept parental disciplinary tactics promote children's aggressive behavior. Although the notion of reciprocity has been widely acknowledged, research studies that examined how earlier experiences of negative reciprocity affect later externalizing problem behaviors in a comprehensive theoretical model have been relatively sparse. Using a three-year longitudinal data set including 398 two-parent families from the midwest, the present study developed a conceptual model for testing both cross-lagged and contemporaneous effects of parent-child reciprocity on adolescents' externalizing problem behavior. Structural equation modeling analyses revealed (1) high stability of harsh parenting, aggressive behavior, and externalizing problem behavior, (2) a significant prediction by Times 1 and 2 boys' earlier aggressive behavior of Times 2 and 3 mother's harsh parenting, respectively, (3) a significant role of fathers' harsh parenting in developing both male and female adolescents' externalizing problem behavior, and (4) both cross-lagged and contemporaneous positive relationships between aggressive behavior and externalizing problem behavior. However, there were no significant differences in terms of the cross-lagged versus the contemporaneous effects of the reciprocity between harsh parenting and aggressive behavior on later externalizing problem behavior. The finding of the elicitation of maternal harsh parenting due to adolescent males' aggressive behaviors provides support for control systems theory; the finding of an association between paternal harsh parenting and adolescents' externalizing problem behavior supports coercion theory. The significant positive relationship between aggressive behavior and externalizing problem behavior added empirical evidence to the ongoing controversy in the literature on whether the relationship constitutes what Lytton (1990) calls "the primacy of a child effect" or simply demonstrates the continuity of behavior over time. With respect to the finding that male adolescents' aggressive behavior influenced maternal harsh parenting, future studies need to expand the examination of the reciprocity in the parent-child dyad by including parental psychological well-being in addition to developmental outcomes of children.