Lean Six Sigma is an integrated set of methodologies that encompasses both Lean and Six Sigma concepts. It combines two powerful toolsets to address all aspects of quality, cost, and delivery. Both sets of methodologies have a strong customer and quality focus and rely on continual improvement, which enable them to be very complimentary.
Lean focuses on providing products and services at competitive prices by eliminating waste and its drivers, whereas Six Sigma focuses on minimizing and reducing process variation that cause nonconformities.