Schools contribute significantly to energy consumption in the education sector annually. Adequate design considerations should, therefore, be made to appropriately ensure an efficient thermal environment for teachers and students who are the major occupants of school buildings. For many years, Oman has economically adopted a typical design and construction for schools to satisfy the high enrolment rate across the country. This decision was embraced without considering the variations in climatic conditions in different regions. This study assesses the impact of modifying the courtyard area geometry and construction on the indoor temperature in the adjoining classrooms. A field study was conducted to analyse the actual conditions in typical buildings. This led to the development of simulation models in Design-Builder, upon which parametric analyses were carried out on different levels and orientations. The results showed that the courtyard design has a relative effect on classroom indoor temperature. A significant increase in temperature was observed on all orientations with covered courtyards, bringing about a slow rate of heat loss in the classrooms compared to the uncovered alternative. The study findings demonstrate that passive design measures can prompt major thermal improvement in the indoor environment.