The literature linking adulthood criminality to cumulative disadvantage and early school misbehavior demonstrates that understanding the mechanisms underlying student behavior and the responses of teachers and administrators is crucial in comprehending racial/ethnic disparities in actual or perceived school misbehavior. We use data on 19,160 ninth graders from the nationally representative High School Longitudinal Study of 2009 to show that boys' and girls' negative achievement and negative experiences with teachers relate more closely to school misbehavior than the contextual measures (e.g., negative peer climate, proportion Black) that have often been emphasized as most salient for misbehavior. Differences in negative achievement and experiences completely explain Black boys', Latinx boys', and Black girls' heightened levels of school misbehavior relative to White youth, and Asian boys' and girls' lower levels of school misbehavior. In contrast, differences in negative achievement and experiences only partially explain Latinx girls' higher levels of school misbehavior relative to White girls.