Teachers' social support and classroom management are related to secondary students' achievement, domain-specific interest, and self-concept. However, little is known about whether social support and classroom management shape secondary students' general school adjustment beyond these domain-specific outcomes. To investigate this question, we drew on data from a large longitudinal research project (N = 5,607 secondary students, N = 227 classes). We applied student and teacher ratings of social support and classroom management to investigate their perspective-specific validities for predicting student outcomes. To measure students' school adjustment, we assessed achievement as a domain-specific indicator and school satisfaction, truancy, and self-esteem as more general aspects. Multilevel confirmatory factor analyses showed that both teachers and students distinguished between social support and classroom management. Teacher and student ratings of classroom management largely converged, whereas their perceptions of social support were not statistically significantly associated with one another. In multilevel structural equation modeling, both perspectives uniquely predicted students' school adjustment: Student-rated social support was linked to all outcomes at the student level and to school satisfaction and self-esteem at the class level. Classroom management showed only weak associations with outcomes at the student level, but at the class level, student-rated classroom management was related to truancy and teacher-rated classroom management was linked to school satisfaction and student achievement. These findings highlight the important role of teachers in students' general school adjustment and show the benefit of considering different perspectives and levels of analyses.