Engineer-To-Order (ETO) companies develop complex one-of-a-kind products based on specific customer demands. Given the product uniqueness, the commissioning plays an important role in the product development process. However, the project variety and low data availability hinder the analysis of the commissioning processes. This paper proposes a framework for the structured analysis of commissioning processes in ETO companies by analysing the impacts from product requirements and design on the commissioning performance. A case study presents the practical application of the developed framework.