This research was designed as an initial attempt to assess relational aggression in preschool-age children. Our goal was to develop reliable measures of relational aggression for young children and to use these instruments to address several important issues (e.g., the relation between this form of aggression and social-psychological adjustment). Results provide evidence that relationally aggressive behaviors appear in children's behavioral repertoires at relatively young ages, and that these behaviors can be reliably distinguished from overtly aggressive behaviors in preschool-age children. Further, findings indicate that preschool girls are significantly more relationally aggressive and less overtly aggressive than preschool boys. Finally, results show that relational aggression is significantly related to social-psychological maladjustment (e.g., peer rejection) for both boys and girls.