Oxford bags were a loose-fitting baggy form of trousers favoured by members of the University of Oxford, especially undergraduates, in England during the early 20th century from the 1920s to around the 1950s. The style had a more general influence outside the University, including in America, but has been somewhat out of fashion since then.

The style originated from a ban in 1924 on the wearing of knickers by Oxford (and Cambridge) undergraduates at lectures. The bagginess allowed knickers to be hidden underneath easily. The style was invented by Harold Acton of Christ Church.

The style made a comeback in 1970s Britain, often worn with platform shoes. A popular 1970s Scottish boy band, The Bay City Rollers wore a variant of oxford bags with tartan trimmings that fell short of ankle-length.

Oxford ⁱ/ˈɒksfəd/ is a city in central southern England, the home of the University of Oxford. The city is the county town of Oxfordshire, and forms a district within the county. It has a population of just under 165,000, of whom 153,900 live within the district boundary. It lies about 50 miles (80 km) north-west of London. The rivers Cherwell and Thames (also sometimes known as the Isis locally) run through Oxford and meet south of the city centre.

Oxford has a diverse economic base. Its industries include motor manufacturing, education, publishing and a large number of information technology and science-based businesses.

Buildings in Oxford demonstrate an example of every English architectural period since the arrival of the Saxons, including the iconic, mid-18th century Radcliffe Camera. Oxford is known as the "city of dreaming spires", a term coined by poet Matthew Arnold in reference to the harmonious architecture of Oxford's university buildings. The University of Oxford is the oldest university in the English-speaking world.