Is NYU or Princeton harder to get into?

The biggest practical tradeoff here is selectivity versus breadth: both NYU and Princeton are highly competitive, but Princeton is the tougher admit overall, while NYU enrolls a much larger and more varied applicant pool across many schools and programs. Princeton is one of the most selective universities in the country, and its small undergraduate size makes available spaces especially limited. NYU is also very hard to get into, but it is not as difficult as Princeton in overall admissions.

Part of the difference comes from scale and structure. Princeton has a much smaller undergraduate population and a more uniformly elite admissions bar across the university. NYU is huge by comparison, with multiple undergraduate colleges and programs, so selectivity can vary somewhat depending on whether you are applying to something like Tisch, Stern, or a less capacity-constrained school.

For building a college list, Princeton should clearly be treated as a very high reach for almost everyone, including top applicants. NYU can also be a reach, especially for popular programs, but for some students it may sit a notch below Princeton in difficulty. That means they should not really be grouped together as equally hard in the broadest sense.

So if your question is simply which one is harder to get into overall, the answer is Princeton. NYU is still a selective school and not close to easy, but Princeton is in a more extreme tier of admissions difficulty.