EU Directive 2014/24 on public procurement aims to establish public procurement as a strategic market-based instrument which is to be used in order to achieve sustainable development, while ensuring the most efficient use of public funds. In order to achieve these aims, the Directive includes numerous references to the environment in its detailed provisions, as well as states that environmental law must be respected as a principle of procurement. At the same time, the Directive’s strengthened focus on the environment is accompanied by increased references to efficiency, best value for money, and competition. Moreover, it includes competition as another principle of procurement. This dual development of EU public procurement law could be understood as contradictory in the sense that the principle of competition could be viewed as a limit to green public procurement. Conversely, green public procurement has been perceived as an obstacle to competition by some Member States. Addressing the uncertainty arising from this development of the law, the present study analyses the implications of the principle of competition for green public procurement. It may provide guidance on this matter for the EU and the national courts, the EU legislature, contracting authorities and firms participating in public procurement, as well as legal practitioners. Dagne Sabockis works with public procurement and competition law at the law firm Vinge, and teaches law at Stockholm School of Economics and Stockholm University.