Six Sigma is the concept of improving the quality by reducing process variations, making continuous improvements, reducing defect rates and improving the processes. The Definitions & Concepts of Six Sigma have been changing since its evolution as per the requirements of time & market conditions. Initially, the concept of Six Sigma focused on defect reduction, then on cost reduction along with value addition and now on value creation, improving the process capability making the process more reliable along with reducing eight wastes of industry & improving the competitiveness of a product with least possible costs incurred on it. This study presents the literature review of the works already done in the field of Six Sigma Implementation by the various authors till now. The findings of this paper will be the basis of my further research in this field by developing appropriate research methodology needed to achieve the objectives set by me for my research work.