In this study, it was aimed to examine teachers' attitudes and challenges they experience concerning Individualized Education Program (IEP). Explanatory sequential design, one of the mixed methods, was used in this study. The study group of this study consists of 100 teachers working in the central districts of Van, Turkey within 2019-2020 academic year. In data collection, the scales of "Determining the Attitudes towards IEP Preparation Process", "Determining the Challenges Concerning IEP Preparation Process" and a semi-structured interview form were used. Findings demonstrated that teachers have positive views about the IEP process, and the implementation of IEP is useful and essential. Concerning the challenges they experience during the IEP process, the teachers think that they do not have sufficient information about the planning, implementation and assessment/evaluation processes of IEP, the school/classroom is physically inadequate, and the classes are crowded in the implementation of IEP. In addition, it was found that as the positive attitudes of the teachers towards IEP increased, the challenges they encountered during the IEP process decreased. Based on the results of this study, it can be suggested that teachers should receive in-service training, physical conditions should be improved, the class size should be reduced, and cooperation should be provided between the family, classroom teachers and guidance counselor in order to conduct IEP in a healthier way.