St Cross College, known colloquially as StX, is a constituent college of the University of Oxford in England. Founded in 1965, St Cross is an all-graduate college with gothic and traditional-style buildings on a central site in St Giles', just south of Pusey Street. It aims to match the structure, life and support of undergraduate colleges, with the relaxed atmosphere of an all-graduate college.

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.