The current study adopts a relational vulnerability model to examine the association between hostile attribution bias and relational aggression. Specifically, the relational vulnerability model implicates the interactive effects of a number of relational risk factors in the development of relational aggression. A sample of 635 3rd, 4th, and 5th grade students (50.2% females) completed a self-report measure assessing hostile attribution bias and emotional distress for relational provocations. Peer nominations and teacher reports of relational aggression and relational victimization were also collected. Results supported the relational vulnerability model for girls only. Specifically, hostile attribution bias was associated with relational aggression only when relational victimization and emotional distress were also high. Implications for future research and clinical practice are discussed.