The purpose of the research is to assess knowledge levels of physical education teachers in inclusive education in secondary schools. For the research, the survey method was employed. It consisted of 55 physical education teachers employed in 47 secondary schools included in inclusive education program under Kocaeli Provincial Directorate of National Education. Field experts (faculty members) and the related general directorates were consulted for the face and content validity of the questionnaires used in a study by Varol (2010) to assess inclusion applications in primary schools and the teacher questionnaire developed as a result of these views was used following the adaptation process to physical education teachers. As a result of the study, it was concluded that physical education teachers employed in inclusive secondary schools did not have sufficient information about inclusion and needed further information, they did not get any information before inclusive education and did not have enough preparations for inclusion, they did not get any aid/support in inclusion applications, there were no special education teachers in inclusive secondary schools, inclusive students did not have sufficient supportive educational services, teachers did not adequately apply individualized education programs and there were no education materials.