This short-term longitudinal study examined the direct association between relational victimization and relational aggression over a five-month period, and proposed that hostile attributional bias for relational provocations mediated this association. Participants were 140 preadolescents (aged 9 to 11 years) in grades four and five. Relational victimization and relational aggression were assessed from self-reports. Hostile intent attributions were measured from preadolescent's responses to hypothetical provocation situations that depicted ambiguous relational aggression among peers. Concurrent and longitudinal findings revealed that more relationally victimized preadolescents were also more relationally aggressive toward their peers. Hostile attributions partially mediated the concurrent association between relational victimization and relational aggression at T1 only. Boys reported significantly higher levels of physical victimization, physical aggression, and relational aggression than girls. Implications for prevention programs are discussed.