Over the past few decades, the evaluation of the seismic vulnerability of existing buildings has received increasing attention due to the considerable damage observed in newly constructed structures, even those designed in accordance with contemporary seismic design codes. These observations have raised serious questions regarding the adequacy and reliability of past design practices and the extent to which buildings constructed under earlier editions of seismic design standards can meet current performance expectations. In Iran, the Iranian Seismic Code, Standard No. 2800, has undergone several revisions to incorporate advances in research, seismic hazard assessment, and design philosophy. However, a large number of existing buildings across the country, including vital facilities such as schools, were designed and constructed based on the earlier editions of this standard. Understanding the seismic performance of such buildings is therefore essential for risk mitigation, decision-making, and prioritizing retrofit strategies. The main objective of this research is to develop a comprehensive set of seismic fragility curves for reinforced concrete (RC) school buildings located in Isfahan Province. The selected buildings were designed according to different editions of Standard No. 2800 and represent various combinations of seismic hazard levels, structural heights, and local soil conditions. The building typology studied consists of RC moment-resisting frames, which are common in school construction throughout Iran. For a systematic and consistent evaluation, the selected models were classified into 14 categories based on four primary parameters: building height (low-rise, mid-rise, or high-rise), edition of the design code, regional seismic hazard intensity, and soil type according to the Iranian geotechnical classification system. To assess the seismic vulnerability of these representative structures, nonlinear Incremental Dynamic Analyses (IDA) were performed using the OpenSees software platform. Each two-dimensional analytical frame model was subjected to a suite of 22 far-field and 12 near-fault ground motion records, carefully selected and scaled according to the seismic hazard level. The analyses were carried out until global structural collapse or significant loss of lateral load-carrying capacity was observed. The spectral acceleration at the fundamental period of vibration, assuming 5% damping, was adopted as the intensity measure (IM), while the maximum inter-story drift ratio was used as the engineering demand parameter (EDP) and damage index. Utilizing the statistical results of the IDA curves, seismic fragility functions were derived for different performance limit states, ranging from slight to complete structural damage. The developed fragility curves clearly demonstrate that the seismic vulnerability of RC moment-resisting school buildings increases with building height. In other words, taller buildings exhibit a higher probability of reaching or exceeding a given damage state under the same seismic intensity. Furthermore, the comparison between buildings located in moderate and high seismic hazard zones revealed an unexpected yet consistent trend: the probability of damage exceedance is higher for buildings situated in moderate hazard regions. This may be attributed to the fact that structures in higher hazard zones are typically designed with greater strength and ductility requirements, leading to improved seismic performance. The results of this study provide valuable insights for engineers, researchers, and policymakers seeking to evaluate and improve the seismic resilience of existing school buildings designed under different generations of the Iranian Seismic Code. The derived fragility curves can be effectively used in regional loss estimation, probabilistic risk assessment, and the prioritization of retrofit interventions, contributing to safer educational environments and more resilient communities in earthquake-prone regions.