Background: The purpose of this study is to provide an examination of the psychometric properties and correlates of a parent-report measure of the forms and functions of aggression. Objective: We sought to explore the potential independent association of parent-reported forms and functions of aggression to several important variables commonly associated with aggression (i.e., callous and unemotional traits, delinquency, and emotional and behavioral dysregulation) while controlling for self-reported aggression. Further, we examined whether parent-reported reactive and proactive aggression showed similar divergent correlates as self or other reports of aggression. Methods: 141 community youth aged 11-17 (mean age = 13.55; SD = 2.18; 51% female) and their parents/guardians participated in the study. Parent and self-report questionnaire data were collected during a laboratory visit. Results: Results suggest that parent-reported aggression was associated with adolescent adjustment variables while controlling for self-reported aggression, and that parent-reported reactive and proactive aggression showed divergent associations with adjustment correlates similar to those often found for self-reported reactive and proactive aggression. Conclusions: This study provides a promising initial examination of the utility of a parent-report measure of forms and functions of aggression in adolescents. These findings have implications for the assessment of the forms and functions of aggression in adolescents and suggest that using parents as informants (in addition to other reporters) provides useful information about youths' behavior.