The relationship between student behavior change and teacher reactions to the change was investigated. One fifth-grade teacher served as the subject and two students in her class were employed as teacher change agents. In a multiple baseline design, the students' disruptive behavior (the independent variable) was modified without the teacher's knowledge. The teacher's reactions toward the students (the dependent variable) was monitored on several dimensions including: teacher behavior, teacher attitude toward students, and the quality of teacher verbal statements. Results indicated that student behavior change influenced the teacher's behavior. Implications are that students possess potent reinforcing properties for teachers and that students should be trained to be effective students.