Purpose: This paper is one of seven in this volume that aims to elaborate different approaches to quality improvement in education. It delineates a methodology called Six Sigma. Design/methodology/approach: The paper presents the origins, theoretical foundations, core principles and a case study demonstrating an application of Six Sigma in a school-community partnership in Milwaukee, Wisconsin. Findings: The core principles underlying the approach are decreasing variability or unreliability in organizational work processes, eliminate waste or activity that does not add value to desired outcomes, identify defects and decrease their incidence, reduce the cost of work processes, and improve beneficiary/client satisfaction levels. The steps in this statistics-dependent method are design, measure, analyze, improve and control. Originality/value: Few theoretical treatments and demonstration cases are currently available on commonly used models of quality improvement that might have potential value in improving education systems internationally. This paper fills this gap by elucidating one promising approach. The paper also derives value as it permits a comparison of the Six Sigma approach with other quality improvement approaches treated in this volume.