Lean Six Sigma (LSS) has been pushing many organizations around the world, enhancing their business through quality and performance improvement. Several studies point out that obtaining the expected results from that approach depends on a successful LSS implementation. Some studies have developed guidelines that help organizations to successfully adhere to it, however, few consider organizations whose production systems are of the Engineer-to-Order (ETO). This work proposes itself to fill this gap by developing an implementation guideline based on the check-action-plan-do (CAPDo) cycle. For this, an LSS maturity measurement tool is developed from Critical Success Factors (CSF) in the implementation of LSS and a Maturity Model (MM) - both raised in the literature through Scope Review. By using a hybrid methodology, the definition of the items to be assessed and their weights is carried out from experts panels, applying the Item-Objective Congruence (IOC) method and the Analytic Hierarchy Process (AHP) method. For model validation and adjustments, an Action Research is carried out in a media industry company that is in the LSS implementation phase.