Servitization allows manufacturing companies to enrich their value proposition with services. It enables them to differentiate their offers from competitors, while capitalizing more on digital technologies. Servitization practices such as maintenance services, training and advisory, or rental and leasing solutions are widespread among many sectors. In this paper, we focus on the ETO context. We explore the literature to capture how and why servitization has been adopted by ETO companies. Based on our findings, we build a theoretical framework that we partly validate through an analysis of secondary sources. We conclude the paper with possible future research directions.