The aim of this current research was to investigate airborne fungi in indoor environments at primary schools. The study also examined the correlation between these fungi and building characteristics, as well as some geographical and meteorological parameters. To achieve this aim, a passive sampling method was used. In this study, 148 samples were collected from the indoor environments of 24 schools located in Qom, Iran. To collect the samples, passive sampling was performed using Petri plates containing Sabouraud dextrose agar (SDA). The characteristics of school buildings were evaluated by checklist. The mean ± SD fungal load of indoor air in selected schools was found to be 10.1 ± 14.0 colonies (CFU/dm2 / h). According to the IMA standard, the majority of the classes (71.7%) were in very good condition. The dominant species were as follows: "Aspergillus niger," "Aspergillus candidus," and "Aspergillus flavus." Furthermore, the fungal load of girls' schools was significantly higher than that of the boys' schools (p < 0.05). The correlation analysis using the Pearson test showed that there was a direct correlation between the mean fungal load of classrooms and the number of students (p < 0.01). The highest concentration of fungi was found on the ground floor and in poor ventilation conditions (p < 0.05). During the study, it was found that schools located in the western part of Qom, Iran, had a higher concentration of fungi. This can be attributed to their exposure to the prevailing winds and the penetration of outdoor dusty air into indoor environments. The large number of students in each class and the inappropriate ventilation, which are the causes of airborne culturable fungi of these classes, call for the need for proper operation of school buildings.