Oxbridge is a portmanteau of the universities of Oxford and Cambridge, the two oldest, wealthiest, and most prestigious universities of the United Kingdom. The term is used to refer to them collectively, in contrast to other British universities, and more broadly to describe characteristics reminiscent of them, often with implications of superior social or intellectual status or elitism.

Although both universities were founded more than eight centuries ago, the term Oxbridge is relatively recent. In William Makepeace Thackeray's novel Pendennis, published in 1850, the main character attends the fictional Boniface College, Oxbridge. According to the Oxford English Dictionary, the first recorded use of the word was by Virginia Woolf, who, citing Thackeray, referenced it in her 1929 extended essay A Room of One's Own. The term was used in the Times Educational Supplement in 1957, and the following year in Universities Quarterly.

When expanded, the universities are almost always referred to as "Oxford and Cambridge", the order in which they were founded. A notable exception is Tokyo's Cambridge and Oxford Society; this probably arises from the fact that the Cambridge Club was founded there first, and also had more members than its Oxford counterpart when they amalgamated in 1905.

In addition to being a collective term, Oxbridge is often used as shorthand for characteristics the two institutions share:

The word Oxbridge may also be used pejoratively: as a descriptor of social classes (referring to the professional classes who dominated the intake of both universities at the beginning of the twentieth century), as shorthand for an elite that "continues to dominate Britain's political and cultural establishment" and a parental attitude that "continues to see UK higher education through an Oxbridge prism", or to describe a "pressure-cooker" culture that attracts and then fails to support overachievers "who are vulnerable to a kind of self-inflicted stress that can all too often become unbearable" and high-flying state school students who find "coping with the workload very difficult in terms of balancing work and life" and "feel socially out of [their] depth".

The Sutton Trust maintains that the University of Oxford and the University of Cambridge "recruit" disproportionately from eight schools (Westminster School, Eton College, Hills Road Sixth Form College, St Paul's School, Peter Symonds College, St Paul's Girls' School, King's College School, and Magdalen College School). They examined published admissions data from 2015 to 2017 and found that, out of the 19,851 places during the three years, the eight schools accounted for 1,310, whereas 2,900 other schools with historically few admissions to Oxbridge accounted for 1,220.

Other portmanteaus have been coined that extend the term Oxbridge, with different degrees of recognition:

The Loxbridge term is also used referring to the golden triangle of London, Oxford, and Cambridge. It was also adopted as the name of the Ancient History conference now known as AMPAH.