This study examined adolescents' patterns of beliefs about aggression, and how these patterns relate to aggressive and prosocial behavior, and to risk factors associated with aggression. A sample of 477 sixth graders from two urban schools and a school in a nearby county completed measures of beliefs, behavior, and individual, peer and parental factors associated with aggression. Teacher ratings of participants' behavior and emotion regulation were also obtained. The urban sample was 84% African American; the county school was in a rural fringe area with a student population that was 45% Caucasian and 40% African American. Latent class analysis of items on a beliefs measure supported hypotheses predicting three groups: (a) a Beliefs Against Fighting (BAGF) group that opposed the use of aggression (31% of the sample); (b) a Fighting is Sometimes Necessary (FSNEC) group that endorsed beliefs that fighting is sometimes necessary or inevitable (41%), and (c) a Beliefs Supporting Fighting (BSUPF) group that supported aggression across multiple contexts (28%). Differences across groups were found on race/ethnicity and family structure, but not on gender. Significant differences were also found such that the FSNEC group fell between levels of the BAGF and BSUPF groups on most measures. In contrast, the FSNEC and BAGF groups both differed from the BSUPF group, but not from each other on measures of empathy, perceived effectiveness of nonviolence and aggression, and parental messages supporting nonviolence. These differences suggest the need for tailoring prevention approaches for subgroups of adolescents who differ in their patterns of beliefs.