Background: Organisational culture (OC) plays an increasingly important role in shaping practices and management approaches in state-owned enterprises (SOEs). Despite this importance, there is a paucity of research addressing the validation and contextual adaptation of the Organisational Culture Assessment Instrument (OCAI) for use in SOEs, particularly in developing countries such as South Africa. Purpose: This study aims to validate the OCAI in the context of South African SOEs by conducting rigorous psychometric assessments and confirmatory factor analyses (CFA). Methods: This study followed a positivist research philosophy and adopted a quantitative approach with a stratified sample of (N=373) permanent employees in a South African state-owned enterprise. After an initial screening, psychometric testing and confirmatory factor analyses were conducted to determine the internal reliability and construct validity of the instrument. Results: The results show that the OCAI represents a four-dimensional structure of organisational culture with good internal consistency for clan culture, adhocracy culture, market culture and hierarchy culture. The CFA showed that the loading coefficients of most factors of the culture model had moderate to high values ranging from 0.39 to 0.92. Furthermore, the results showed that the model had an adequate fit. Conclusion: The results of the study indicate that the OCAI has good reliability and validity, which speaks in favour of its applicability in SOEs in South Africa and similar cultural contexts