ABSTRACT Modern society has a higher demand for quality than it had before. There is a Plethora of quality improvement techniques available which makes it harder for companies to decide which one to apply. They need support in this decision and in knowing how to apply the chosen techniques, if they want to improve their business and stay competitive. Six Sigma approach is a very successful manufacturing quality improvement tool. In the last two decades, it has helped many companies to success. Recently, the Six Sigma approach was introduced in the software development industry. Some software companies have been trying to adapt Six Sigma for their business and development processes. But there are misconceptions about the applicability of Six Sigma in software‟s. Furthermore there is no generic software quality improvement solution based on Six Sigma. So there is a demand to debunk the misconceptions related to the applicability of Six Sigma. And to develop a generic software company quality improvement solution based on Six Sigma approach. In this thesis we take a first step towards such a solution. The thesis starts from Six Sigma concept identification and manufacturing investigation. After conducting interviews, a case study and several case studies reviews, we detail our method. We expect thesis result to be useful for software companies when applying Six Sigma in their company for process improvement. Keywords: Software Quality, Quality Improvement Tool, Six Sigma and Process Improvement