Early adolescence is a time of increased stress and risk for poorer psychosocial functioning, but few studies have explored the relationship between stress and psychosocial functioning in the context of teacher-student relationships during early adolescence. This study used a two-wave longitudinal design to investigate the unique and interactive effects of stress and teacher-student relationships on anxiety/depression, aggression, and rule-breaking behaviors. The sample included 288 sixth- and seventh-grade students (M[subscript age] = 12.01; 54% females; 47% Black, 36% White, 9% Hispanic) and their parents and teachers. Student-perceived stress and teacher-reported teacher-student conflict were related to more aggressive and rule breaking behaviors at Wave 1; perceived stress also predicted more anxiety/depression symptoms at Wave 1. Further, teacher-reported teacher-student closeness predicted less aggressive behaviors over time. The findings suggest that interventions that promote stress management and positive teacher-student relationships may reduce adjustment problems concurrently and over time among early adolescents. [For the corresponding grantee submission, see ED630189.]