The purpose of this study was to extend the current literature on forms (i.e., physical and relational) and functions (i.e., proactive and reactive) of participants’ cognitions and beliefs about aggressive behavior. Participants included an ethnically diverse group of emerging adults (N = 165; M = 19.05 years; SD = 1.55) and completed a battery of self-report instruments. Gender differences for subtypes of physical aggression were found. Impulsivity was associated with all subtypes of aggression. Results showed that reactive physical aggression was uniquely associated with hostile attribution biases for instrumental provocation situations. Reactive relational aggression was uniquely associated with hostile attribution biases for relational provocation scenarios. Findings indicated links between self-reported subtypes of aggressive behavior and normative beliefs of aggression. Ways in which this study extends the extant literature are discussed.