This multilevel study examined the relationships between moral climate factors and prosocial as well as antisocial behaviors inside and outside the school (school misconduct, delinquent behavior, and vandalism). The moral climate factors were punishment- and victim-based moral orientation, relationships among students, and teacher–student relationships. The analyses of data from 670 students in 69 classes showed that the classroom-level variables only had a significant impact on misconduct at school of students aged 12 to 20. For the other outcome variables, the student-level variables (student and teacher–student relationships, but especially students’ moral orientation) were significant. A novel finding was that a positive teacher–student relationship not only proved to be related to less misconduct inside the school but also to less delinquent behavior and vandalism outside the school. This indicates that the teacher is an important socializing agent for adolescent behavior in general.