This PhD thesis deals with IP-competition conflicts and how the EU Courts have addressed them over time. It seeks to answer the question of how the reasoning of EU Courts in these cases has been affected by three crucial evolutionary moments in EU law: (1) the Europeanization of IP law (2) the modernization of EU competition law and (3) the elevation of the Charter of Fundamental Rights of the European Union to a primary source of EU law. The first two chapters provide the theoretical framework of the thesis. The first chapter provides a detailed overview of the three crucial evolutionary moments in EU law mentioned above. The second chapter provides an overview of theories about the legal reasoning of EU Courts and about the different approaches that the courts have adopted when deciding IP-competition conflicts. Five such approaches, or judicial lenses, are identified: an economics, a conflict of laws, a conflict of competences, a constitutional and a private law approach. It is shown that these five different approaches can be linked to the three evolutionary moments at the IP-competition interface in EU law. Chapters three to five trace the theoretical insights from the first two chapters in three case studies on specific business methods having given rise to IP-competition conflicts before EU Courts: (i) selective distribution systems, (ii) digital platforms and restrictions of access, and (iii) lock-in strategies on aftermarkets, in particular in the online environment. The case studies analyse how these comparable factual situations of IP-competition conflicts have been treated on the one hand under EU competition law and on the other under EU IP law. In each case study, the legal reasoning is identified and compared between EU competition and IP law. The main finding in the case studies is that EU Courts treat the spheres of EU competition law and IP law as wholly separate. This has led to quite diverging approaches in comparable cases of IP-competition conflicts depending on whether the cases are brought under EU competition law or IP law, jeopardizing the systemic coherence of EU law and disturbing the CJEU’s dialogue with national ii courts. This situation is not sustainable. In an economic environment where the EU’s economies are increasingly depending on e-commerce and digital assets often protected by IP, IP-competition conflicts are bound to increase. To ensure a legal environment that provides legal certainty and equal conditions for firms to thrive across EU Member States without hurting consumers, a more coherent and improved methodological guidance on how to address IP-competition conflicts is needed. The aim of this thesis is to provide a first step in this direction.