The University of Oxford (informally "Oxford University", or just "Oxford"), located in the city of Oxford, England, is the oldest university in the English-speaking world. It is also regarded as one of the world's leading academic institutions. The name is sometimes abbreviated as Oxon. in post-nominals, from the Latin "Oxoniensis" although Oxf is sometimes used in official publications.

The university traces its roots back to at least the end of the 11th century, although the exact date of foundation remains unclear. After a dispute between students and townsfolk broke out in 1209, some of the academics at Oxford fled north-east to the town of Cambridge, where the University of Cambridge was founded. The two universities have since had a long history of competition with each other (see Oxbridge rivalry).

The University of Oxford is a member of the Russell Group of research-led British universities, the Coimbra Group (a network of leading European universities), the League of European Research Universities, and is also a core member of the Europaeum. Academically, Oxford is consistently ranked in the world's top ten universities. For more than a century, it has served as the home of the Rhodes Scholarship, which brings highly accomplished students from a number of countries to study at Oxford as postgraduates.

The university makes up a corner of the so-called 'Golden Triangle' of top British research universities.