Social learning models of the intergenerational transmission of aggression were tested for an at-risk sample of young-adult males who entered a longitudinal study (the Oregon Youth Study) in Grade 4, and were assessed with a female partner in young adulthood (17 to 20 years of age). The associations of two family process variables, namely parental dyadic aggression and unskilled parenting in late childhood and early adolescence and the son’s later aggression toward a partner, were examined. Parental antisocial behavior was hypothesized to be associated with both family process factors. Unskilled parenting was hypothesized to play a key role in the son’s later aggression to an intimate partner, mediated by his development of antisocial behavior by adolescence. Fully prospective models were tested using structural equation modeling with multimethod, multiagent data, including both observed and reported aggression to partner. Findings indicated evidence for the major hypothesized pathways through unskilled parenting practices and the boys’ antisocial behavior in the intergenerational transmission of aggression.