The purpose of this study was to investigate the impact of the maintenance management system (MMS) on production output and profitability (PO&P) at the Petroleum Oil and Gas Corporation of South Africa (PetroSA) GTL Refinery as a source of competitive advantage. State-Owned Companies and, or more specifically the PetroSA GTL Refinery must maintain its strategic importance for government fuel security but, at the same time, it must compete against private refineries in terms of achieving high production volumes, maximising profitability and to maintain its stake of 6.5% of the available production capacity. The literature review for this study suggested that the maintenance management system (MMS) impacts positively on production output and profitability (PO&P). The MMS has a tremendous influence on PO&P at the PetroSA GTL Refinery. Using a quantitative research design, cross-sectional research survey and the Maintenance Scorecards (MS) assessment tool, this study was conducted on six areas of the PetroSA GTL Refinery. Two population groups, namely production and maintenance groups participated in the survey. Fifty-six respondents belonged to the maintenance group and thirty-eight respondents belonged to the Production Group. All the Maintenance and Production Group respondents completed the MS questions designed to fit the characteristics of these population groups. Correlation analysis in terms of the means, standard deviations, gap analysis, Pearson product moment correlation coefficient (r) as well as the coefficient of determination (R²) was used to analyse the data. The findings of the study indicated a moderate positive linear correlation between the MMS and PO&P. Recommendations based on the findings were tabled in chapter 7 to improve and enhance production perspective (asset health gap), safety perspective (asset prioritisation gap) and the learning and growth perspective (skills and working condition gap). / Business Management / M. Com. ((Business Management)