This chapter discusses the classification of digital services using the GATS services classification system. The chapter first elaborates on how services are classified under the GATS and the role of the evolutionary approach, the customary rules of treaty interpretation, the existence of integrated services and the focus on outputs. The chapter subsequently distinguishes between three classification methodologies (the textual approach, the component-based approach and the teleological approach) and explains why the technological approach to services classification is preferable. The teleological approach is then applied to examples of both digital infrastructure services and digitally enabled services. The chapter elaborates on the distinction between transmission and content, the confusion on how to classify ‘new’ services and the misplaced focus on the service suppliers’ revenue source. This chapter thereby proposes a clear and consistent classification methodology that allows for straightforward classification of digital services.