In the traditional sense, IT has often been viewed as a contributor to waste within lean production. However, as the business world changes and competition from low-cost countries increases, new models must be developed which deliver competitive advantage by combining contemporary technological advances with the lean paradigm. In order to make a contribution within this field of research, we evaluate the support functionality of Manufacturing Execution Systems (MES) for lean production. We address the fundamental principles of lean production and compare them to the functionality offered by MES, and by combining existing theoretical contributions with practical insights we develop a five-stage capability maturity model for MES support for lean production.