The aim of this study is to look into the reliability and validity of the multidimensional Allen and Meyer’s (1990) organizational commitment (OC) scale in a financial organization belonging to the public sector in Greece, as well as the relationship between the factors of the questionnaire. Using stratified random sampling, 205 employees were selected to participate in the survey, currently working in the aforementioned organization. The necessary ethical issues of participation in the research were observed. The reliability of the questionnaire was examined using Cronbach’s alpha coefficient, while the validity was checked using factor analysis. Correlations were investigated using Spearman’s coefficient. Results confirmed that affective, continuance and normative dimensions of commitment were statistically reliable and valid while measuring the levels of Greece’s public sector OC with a statistically significant positive correlation between them. The findings are consistent with the results of previous studies that Allen and Meyer’s (1990) OC scale is the most reliable, validated, well-established and widely used instrument which provides a true picture of the relationship between various dimensions and sub-dimensions of commitment (Khajuria & Khan, 2022).