Over the past few decades, Six Sigma has diffused to a wide array of organizations across the globe, which has been fueled by the reported financial benefits of Six Sigma. Implementing Six Sigma entails carrying out a series of Six Sigma projects that improve business processes. Scholars have investigated some mechanisms that influence project success, such as setting challenging goals and adhering to the Six Sigma method. However, these mechanisms have been studied in a piecemeal fashion and do not provide a deeper understanding of their interrelationships. Developing a deeper understanding of these mechanisms helps identify the contingency and boundary conditions that influence Six Sigma project execution. Drawing on Sociotechnical Systems theory, this research conceptualizes and empirically examines the interrelationships of the key mechanisms that influence project execution. Specifically, we examine the interrelationship between Six Sigma project goals (Social System), adherence to the Six Sigma method (Technical System), and knowledge creation. The analysis uses a mediation-moderation approach which helps empirically examine these relationships. The data come from a survey of 324 employees in 102 Six Sigma projects from two organizations. The findings show that project goals and the Six Sigma method can compensate for one another. It also suggests that adherence to the Six Sigma method becomes more beneficial for projects that create a lot of knowledge. Otherwise the method becomes less important. Prior research has not examined these contingencies and boundary conditions, which ultimately influence project success.