The research's aim is to assess the services offered by Greek public secondary education schools, with the intention of identifying any discrepancies between students' expectations and their perceptions of the final services provided. The gaps discovered indicate that the school's educational services are not meeting student expectations in the five quality dimensions of the SERVQUAL model. To be specific, the average expectations are 4.44, perceptions are 3.11, and gaps are -1.33. The schools examined had a greater discrepancy in the dimensions measuring safety and emotional understanding, which was observed. The fact that the 5 factors are correlated with each other indicates the model's reliability. However, in relation to the independent variables of gender, age, and class, there appears to be a positive correlation across all factors, which is very weak and not statistically significant. In contrast, a low negative correlation appears to be present between only the demographics being considered. Therefore, demographic characteristics do not affect the quality of education in secondary schools. Our findings benefit decision-makers by assisting them in taking corrective actions necessary to enhance the quality of services provided by schools as part of a continuous improvement process in order to achieve a higher level of excellence.