Lean Six Sigma (LSS) has established itself as one of the key business process improvement strategies available to companies today. With roots based in the single strategies of Lean and Six Sigma, LSS offers a dual strategy towards systematically reducing waste and increasing value whilst resolving Critical to Quality issues that affect consistency and repeatability in a product and process. This paper proposes a Strategic Lean Six Sigma Framework (SLSSF) that attempts to create an integrated approach between the Lean and Six Sigma elements and one that is capable of achieving greater efficiency of production whilst also ensuring that CTQ issues are eradicated from the production process. The case study involves the application of the SLLF in an aerospace manufacturing company. The work highlights the key stages of the framework before closing with an analysis of its effectiveness and the difficulties encountered in its application. When the LSS model was implemented it achieved significant improvements in business performance. The key improvements were seen as; Build time reduction of 20.5%, improved on-time-in-full (OTIF) delivery to customer by 26.5%, reduced Value Added time by 5% and, reduced Non-value added time by 44.5%. Also, estimated financial savings of over £2 Million are proposed.