This study found modest links between overt and relational aggression and maladaptive SIP (tendency to misperceive threats, hostility, and demeaning treatment in social interactions) among this female adolescent sample; however, in the comparison of girls with and without ADHD, the relationships between aggression and SIP were stronger for the girls without ADHD. These modest relationships between aggression and SIP in this sample contrast with the abundance of evidence that has linked aggression and SIP in other studies, largely with male children. This difference was unexpected and challenges the relevance of the SIP model for adolescent girls and for relational aggression. It may be that the exclusively verbal hypothetical nature of the scenarios in the vignettes used to assess SIP in the current study were not good measures of SIP biases in girls and/or adolescents. On the other hand, the finding that the link between SIP biases and aggression were stronger among non-ADHD girls is similar to other studies that have documented the link between childhood covert antisocial behavior and adolescent overt aggression only for non-ADHD boys. Suggestions are offered for future research in this area. During childhood, girls in the sample participated in summer camps where peer rejection, overt physical aggression, and relational aggression were assessed by means of multiple informants and methods. Approximately 4 1/2 years later, these girls participated in followup assessments, during which they completed a commonly used vignette procedure for assessing SIP. Overt and relational aggression were again assessed through multiple informants. 3 tables and 55 references