Is the University of Copenhagen harder to get into than Princeton?

No. Princeton is much harder to get into in an overall admissions sense.

Princeton uses a highly selective, holistic process for a very small entering class, and it turns away many applicants who already have top grades, rigorous coursework, and strong extracurricular profiles. For most students, especially international applicants, admission is extraordinarily competitive in a way that is not really comparable to a large public university system.

The University of Copenhagen works more like a national public university, where admission is often driven more by whether you meet the academic requirements for a specific program and, in many cases, by available seats and credential equivalency. That can still make some programs competitive, but the baseline question is usually whether you qualify for that course of study rather than whether you stand out across every dimension of your application.

Another big difference is scale and purpose. Copenhagen serves a broad public higher education role in Denmark and offers many programs with structured entry requirements, while Princeton is a small private university that builds a class through intensive selection. So in a general, school-wide comparison, Princeton is the tougher admit by a wide margin, even though certain University of Copenhagen programs can still be difficult for applicants who do not match the required academic background.