App-based for-hire transport services make mobility more efficient by better matching supply and demand. They offer passengers a high degree of predictability and ease of use, and drivers with highly flexible work opportunities. Yet the popularity of app-based services has eroded the market share of traditional taxi operators, causing significant friction that is manifesting itself in court cases and even physical violence. How to regulate these new services is therefore high on the agenda of governments around the world. This study, commissioned by the Portuguese Institute for Mobility and Transport, reviews legislation and regulatory frameworks for taxi and for-hire transport services in Portugal and six other countries in order to foster an evidence-based discussion of the issue.