This study explored the role of students' externalizing, internalizing, and prosocial behavior and classroom climate in their mental representations of student-teacher relationships. In total, 266 third to sixth graders and 35 teachers participated. Teachers completed questionnaires about students' social-emotional behavior and student-teacher relationships. Relationship perceptions were aggregated to form a classroom climate measure. Students made drawings of themselves with the teacher, which were scored by independent coders on 8 dimensions. Multilevel models indicated that children with externalizing behavior depicted more tension/anger, bizarreness/dissociation, and emotional distance/isolation, and less pride/happiness in their drawings. Internalizing behavior was not associated with their mental relationship representations. Children with prosocial behavior depicted more creativity/vitality and less role reversal and global pathology than less prosocial counterparts. Classroom climate did not moderate linkages between child behavior and mental representations. These findings suggest that overt, rather than covert, behaviors play a role in students' mental relationship representations.