School buildings in developing countries such as Egypt are often designed based on natural ventilation without sufficient consideration of local outdoor environment. The school construction section in Ministry of Education in Egypt, normally, uses the same prototype designs to construct schools across the various regions of Egypt without consideration to the significant variations in climatic conditions all-over the country. Therefore, the indoor environment quality which in turn affects human comfort, health and learning efficiency in those buildings is unknown as the proposed design rely on natural ventilation. The main aim of this study is to assess the existing thermal comfort conditions in the governmental primary schools in Egypt to identify the percentage of the school time the pupils spent in their classrooms within thermal comfort conditions.