Six Sigma is a quality management approach that helps improve process, performance, cut down defects, and boost customer satisfaction across various industries. This review covers the history, key principles, and practical uses of Six Sigma in the. pharmaceutical and manufacturing fields. The method is focused on minimizing variation in processes to achieve high-quality results, with a target of just 3.4 defects per million opportunities. It explores important concepts like DMAIC, Lean Six Sigma, SIPOC, VOC, CTQ, SPC, DOE, and process capability. The review also outlines the different levels of Six Sigma skills and includes case studies from the pharmaceutical industry that demonstrate improvements in productivity, process control, and product quality. In general, Six Sigma assists organizations in enhancing efficiency, lowering costs, improving product quality, and supporting continuous improvement, which leads to better business performance and greater customer satisfaction.