This report, titled "The European Union, Cybersecurity, and the Financial Sector: A Primer," provides an overview of the relationship between the European Union (EU), cybersecurity, and the financial sector. The report is part of the Carnegie Endowment for International Peace's Cyber Policy Initiative Working Paper Series. The authors, Philipp S. Krüger and Jan-Philipp Brauchle, note that the EU has taken significant steps to regulate cybersecurity in the financial sector, with the aim of protecting financial systems and consumers. The report provides an overview of the EU's cybersecurity regulation for the financial sector, including developments in recent years. The authors also provide recommendations for further improving EU cybersecurity regulation in the financial sector. The report is written in a clear and concise manner, making it easy to understand for a wide audience.