Student misbehavior is a pervasive problem and may seriously affect academic achievement. Previous research hints at different effects depending on whether achievement tests or achievement judgments are used as academic outcomes. Previous research also indicates that low achievement can conversely contribute to problem behavior and that low self-esteem--maybe as a consequence of low achievement--is a further source of problem behavior during adolescence. The purpose of this 3-wave longitudinal study was to investigate the complex interplay of externalizing problem behavior, self-esteem, and academic achievement as measured by teacher-given grades and standardized tests in reading comprehension and mathematics. Participants were N = 1,045 junior high school students followed from Grade 5 to Grade 9. Results of structural equation models were fairly consistent across both domains. The findings imply that externalizing problems are reflected in teacher-given grades more than in standardized achievement tests. Furthermore, worse grades were found to have unique detrimental effects on increased future externalizing problem behavior repeatedly over time and across domains. The reciprocal effects between externalizing problems and school grades tend to lead into a downward spiral. Self-esteem negatively affected externalizing problems in earlier grades and served as a partial mediator between school grades and subsequent externalizing problem behavior. The implications for educational practice and future research are discussed.