St Catherine's College is one of the constituent colleges of the University of Oxford. In 1974, it was also one of the first men's colleges to admit women. It has 528 undergraduate students, 385 graduate students and 37 visiting students as of December 2020, making it one of the largest colleges in either Oxford or Cambridge.

The University of Oxford has thirty-nine colleges, and four permanent private halls (PPHs) of religious foundation. Colleges and PPHs are autonomous self-governing corporations within the university. These colleges are not only houses of residence, but have substantial responsibility for teaching undergraduate students. Generally tutorials and classes are the responsibility of colleges, while lectures, examinations, laboratories, and the central library are run by the university. Students normally have most of their tutorials in their own college, but often have a couple of modules taught at other colleges or even at faculties and departments. Most colleges take both graduates and undergraduates, but several are for graduates only.