Developmental trajectories of bullying perpetration were examined across 5 waves of longitudinal panel data among Midwestern middle school students. This study explained an unobserved heterogeneity of subgroups, each having the similar pattern of trajectories and investigated antecedents and consequences of class membership. Growth-mixture modeling yielded 4 groups: (1) "Chronic," (1.2%), (2) "High Declining" (6.2%), (3) "Middle School Peak" (8.1%), and (4) "Low" (84.4%). The overall results revealed that strain variables were found to be significant in the Chronic, High Declining, and Middle School Peak groups. The probability of the Chronic and High Declining groups was high among students with higher impulsivity. Peer delinquency and anger were found to be significant in all three groups. Members of the Chronic group were at the highest risk of sexual harassment and teen dating violence.