The purpose of the thesis was to explore the potential benefits of applying the key principles of Six sigma to Environmental Management Systems (EMSs). A survey of peer-reviewed literature on Six sigma and EMSs was developed. The application of the conceptual framework is demonstrated in a case study. The case study focused on a major Middle Eastern manufacturing company. The case study showed that there were numerous benefits to applying the principles of Six sigma to EMSs. An approach based on the conceptual framework was successful in reducing waste in the case company's paint shop by 80%. Other benefits of applying the conceptual framework included cost reduction, decreased consumption of raw materials, decreased amount of waste water, longer resource life through reduced usage, reduced materials, decreased amount of waste water, longer resource life through reduced usage, reduced emissions, reduced energy consumption, and improved employee health and safety due to less exposure to harmful chemicals. The conceptual framework provides a basis for applying the principles of Six sigma to EMSs. While there is a significant amount of research focusing on the integration of quality and environmental management, the application of Six sigma in the context of environmental management has not been widely discussed. It is anticipated that the results will be of interest to practitioners and researchers in quality and environmental management.