A growing number of researchers are examining how teacher-student relationships contribute to child and adolescent development. Much of this work is based on two distinct theoretical perspectives: social support and attachment. The current study investigates the importance of teacher-student relationships from each of these perspectives among low-income children and youth in a large urban environment. Study 1 focused on 157 children in kindergarten, and Study 2 focused on 171 early adolescents. Findings indicated that teacher social support and teacher-student relationships contributed to indicators of school adjustment among both samples, and to the emotional and behavioral adjustment of early adolescents. Analyses of specific dimensions of relationships suggested that attachment-based constructs were more consistently and strongly associated with adjustment indicators than were teacher social support constructs. Preliminary implications of these findings for future research and practice are discussed.