The purpose of this study was to examine the correlates that define relational aggression among middle school girls, the relationships among these factors, and the association between the correlates of relational aggression and the type of relational aggression (e.g., verbal, withdrawal) exhibited among middle school girls. The findings of this study contribute to the theoretical understanding of relational aggression among middle school girls, suggest evidence-based efficacious interventions, and describe the etiology of internalizing (e.g., individual features: withdrawal, depression) and externalizing (e.g., social features: peer relationships, type of aggression exhibited) behaviors unique to middle school girls. This study examined the relationship between individual factors (e.g., withdrawal, depression) and social factors (peer relationships) related to relational aggression among middle school girls. A convenience sample of 273 middle school students was drawn from similarly sized schools in the southeastern United States. Participants completed a thirty-nine-item survey, which included the Direct Indirect Aggression Scale, the Children's Social Behavior Scale-Peer Report and seven demographic questions. Data were analyzed using chi-square analyses and 3-way ANOVA analyses. Overall, the findings indicated significant relationships between relational aggression and age, relational aggression and socioeconomic status, relational aggression and ethnicity, relational aggression and age, socioeconomic status, and ethnicity. The present study contributes to the theoretical underpinnings of relational aggression in middle school girls by focusing exclusively on this underrepresented population in the literature and posits that developmental theories, social-information processing, and social-psychological models influence the exhibition of externalizing and internalizing behaviors in adolescent girls. Identifying the theoretical foundation for relationally aggressive behaviors among middle school girls has illuminated appropriate interventions for professional counselors to consider in future investigations. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com/en-US/products/dissertations/individuals.shtml.]