Background: High school completion provides health and economic benefits. The purpose of this study is to describe dropout rates based on longitudinal trajectories of aggression and study skills using teacher ratings. Methods: The sample consisted of 620 randomly selected sixth graders. Every year from Grade 6 to 12, a teacher completed a nationally normed behavioral rating scale. We used latent class mixture modeling to identify the trajectories. Results: Participants followed 3 trajectories of aggression ("Low," "Medium Desisting," and "High Desisting") and 5 trajectories of study skills ("Low," "Average-Low," "Decreasing," "Increasing," and "High"). Over three-quarters of the sample were in stable trajectories of study skills over time. Most students in the "High Desisting Aggression" group were in the "Low Study Skills" group, and all students in the "High Study Skills" group were in the "Low Aggression" group. The overall dropout rate was 17%, but varied dramatically across combined aggression and study skills groups, ranging from 2% to 50%. Conclusions: The results highlight the importance of early prevention that combines academic enhancement and behavioral management for reducing school dropout.