The European Commission plays the most prominent role in European merger review, and judicial review of Commission decisions is rare. Despite this, European courts have an essential function in the merger review system in the European Union, both as guarantors of procedural rights and as a vector for the development of the law. This article discusses the procedural aspects of this judicial review, such as when an application can be brought, by whom, and against which decisions, and specific procedures such as interventions, interim relief, expedited procedures, and appeals. We also address the substance of the European courts’ review, in particular on which grounds a Commission decision can be challenged. The article furthermore discusses the consequences of judgments, including the possibility of obtaining damages. We conclude by proposing a possible avenue to improve the process.