Primary school teachers are important mediators in terms of creating a positive climate and displaying appropriate behaviors in inclusion classes. The fact that primary school teachers are good observers of the behavior of students in their classrooms is a very important factor in eliminating or preventing problem behaviors. For this reason, it is important to examine the views of teachers working in inclusion education settings on the behavior of students in their classrooms. The purpose of this research is to reveal the opinions of primary school teachers working in inclusion education settings about the behaviors of students with and without disabilities in their classrooms. The study was conducted using phenomenology design, one of the qualitative research methods. Data were collected through semi-structured individual interviews with primary school teachers working in inclusion settings. The data was analyzed with content analysis, and six themes and 17 sub-themes were found. It was seen that the problem behaviors seen in the inclusion classes were similar to the behaviors seen in the general education classes. According to the findings, most of the teachers did not receive training in problem behaviors. So, courses related to behavior management can be taught in undergraduate programs.