It is plausible that peer aggression-like general forms of aggression-is transmitted from one generation to the next. As such, parental behavior in childhood and adolescence may be associated with offspring aggressive behavior against peers. This study used 1970 British Cohort Study data to test intergenerational transmission of peer aggression. The baseline sample consisted of 13,135 participants. At the first assessment that was used in this study, participants were on average 4.95 years old (SD = 0.79; 48.20% female). At the last assessment, participants were on average 33.88 years old (SD = 0.36; 52.1% female). Models were computed for early and middle childhood, and adolescence. Significant associations between parents' and offspring peer aggression were found in most models - especially when correlating aggression in similar developmental periods for parents and children. Other transmission mechanisms such as genetic transmission may be relevant and should be taken into account in future studies.