many certified ISO 9001 companies are adopting continuous improvement systems based on Lean and Six Sigma principles. Objective: this paper aims to illustrate how Lean and Six Sigma principles, methodologies and tools can be adopted within a quality management system based on the ISO 9001:2015 standard. Results: a new Lean Six Sigma and ISO 9001:2015 integration model is proposed with the explanation of how a wide set of Lean and Six Sigma tools and methods can be applied in different clauses of requirements of the standard. Conclusion: the proposed model contributes to increase the ability to combine a quality management system based on ISO 9001:2015 with a Lean Six Sigma improvement program into a single and integrated management system, thus improving overall efficiency.