In this study, the effect of Preventive Classroom Management Training Program (PCMTP) on approval and disapproval behaviors of teachers working in inclusive classrooms was investigated. The study group consisted of 45 teachers who were working in public schools and had students with special needs in their classrooms. Data were gathered using Teacher Behaviors Observation Form, which was developed by the researcher, and during one lesson which was videotaped in the classrooms of teachers in the experimental group (n= 21) who had a training using PCMTP and the control group (n= 24). The analysis of the research data revealed that PCMTP did not make significant differences in the approval/disapproval behaviors of the teachers in terms of the post-test results but the maintenance results showed that disapproval behaviors of the teachers were significantly lower.