This paper studies the effect of Lean QRM Yellow-belt training programs on employee’s continuous improvement (CI) behavior. Training employees is still the most common approach organizations follow to implement Lean production. However, such training programs do not always have the desired effect. To understand why Lean training programs, such as the Lean QRM Yellow-belt training may or may not lead to expected results, this study draws on a process model to conduct a longitudinal analysis. The results indicate that the Lean QRM Yellow-belt training program positively influences the patterning or shared understanding of lean operating routines, but does not (yet) influence the enactment of lean operating or CI routines. The interaction between enacting and patterning lean operating and CI routines however is necessary to implement lean production and thus influences the potential success of its sustainable implementation. These results pose practical implications on the content and didactical form of teaching in Lean QRM Yellow-belt training programs.