This thesis examines the abuse of dominant positions in Indonesia and the European Union (EU), focusing on its regulation, implementation, and implications. In Indonesia, dominant positions is governed by Law No. 5 of 1999 concerning the Prohibition of Monopolistic Practices and Unfair Business Competition, which defines dominant positions and prohibits their abuse to maintain market fairness. The study analyzes the legal framework and enforcement mechanisms, highlighting challenges faced by the Indonesian Competition Commission (KPPU) in proving and penalizing such abuses. This research addresses the following questions: How do the regulations on the abuse of dominant positions in Indonesia differ from those in the European Union? And How does the implementation of abuse of dominant position cases by KPPU compare to that of the European Commission? The research compares these regulations with the EU’s competition law under Article 102 of the Treaty on the Functioning of the European Union (TFEU). The EU approach emphasizes a comprehensive assessment of market conditions and considers factors such as market barriers, pricing strategies, and consumer impact. Cases such as Pfizer’s in Indonesia and Microsoft’s in the EU demonstrate similarities and differences in regulatory practices, particularly in defining relevant markets and evaluating abusive behavior. This study underscores the importance of effective regulatory oversight to foster fair competition and protect consumer welfare. It recommends strengthening legal frameworks, enhancing institutional capacities, and promoting transparency in enforcement processes. By learning from the EU’s experience, Indonesia could improve its mechanisms to deter market abuse, ensuring a competitive and innovative economic environment.