This note provides an introduction to and overview of the transportation sector in the GreenREFORM model and highlights important observations for the design of the model. The note initially describes the structure of the transportation sector in the Danish National Account statistics including households’ own transportation, and the associated stock of vehicles and fuel consumption. The impact on the environment from transportation is also presented and the role of the transportation sector in the green transitioning of the Danish society is discussed. In this context, the importance of upstream processes such as the production of fuels and refueling infrastructure for fuels is highlighted. Finally, the note gives an intuitive introduction to the transport module in the GreenREFORM model by dicussing the main components of the model.