Recently, shared mobility has become a hot topic in urban mobility discussions. With the scale-up of this model, consumers’ behaviour tends to shift from owning vehicles to paying for temporary access to them. In this chapter, we start from the observation that current vehicle taxes have been conceived in the context of individual car ownership, whereas new car-sharing models are based on providing access to cars for personal use. Using an interdisciplinary approach, we discuss the challenges that business-to-consumer (B2C) car sharing presents for existing car-related tax instruments from a legal and economic viewpoint, using Belgium as an example. We argue that car sharing necessitates careful reconsideration of existing ownership taxes and the planned future introduction of new tax instruments and user charges (eg, road pricing). In particular, B2C car sharing affects both the taxable object, implying a risk of tax revenue erosion, and the taxable person. Moreover, it may engender tax competition. Finally, car sharing also has implications for the implementation of future user charges (eg, road pricing, cordon pricing in cities, kilometre charges). It would thus affect the design of new pricing systems, if these were to be introduced.