In this investigation we examined the relation between teachers' ratings of the classroom behavior of 1,013 fourth graders and student achievement. Students were identified whose behavior was frequently inattentive and withdrawn, and others were identified who were disruptive. Norm-referenced and criterion-referenced achievement tests indicated that inattentive-withdrawn behavior was associated with depressed academic performance, at least to the extent that disruptive behavior was. These results have strong implications for research and practice. Disruptive students tend to draw far more attention from teachers, whereas teachers may overlook inattentive students in spite of the potentially profound effects of nonparticipation in class.