This chapter describes the fourth stage of the Lean Six Sigma implementation process, Improve. With the conclusion of the Analyze stage, we should have a clearer understanding of the root causes that contribute to the problem. The Improve stage takes the process forward by identifying actions that transform these root causes, resulting in an improvement in the effect—Y. This is where ideas and solutions are generated. These various ideas and solutions are then weighed against each other and the most effective solutions are implemented. This chapter will describe the deliverables of the Improve stage along with the tools and techniques to achieve them. At the end of the chapter, we will see the application of this stage to our case study.