Founded in 1893 as Headington United, Oxford United adopted its current name in 1960. It joined the Football League in 1962 after winning the Southern Football League, reaching the Second Division in 1968. After relegation in 1976, between 1984 and 1986 the club earned successive promotions into the First Division, and won the League Cup in 1986. However, Oxford was unable thereby to enter the 1987 UEFA Cup because of the UEFA ban on English clubs in European competitions. Relegation from the top flight in 1988 began an 18-year decline which saw the club relegated to the Conference in 2006, becoming the first winners of a major trophy to be relegated from the Football League. After four seasons, Oxford returned to League Two in 2010 via the playoffs, and six seasons later achieved promotion to League One, after finishing second in League Two in 2016.
The club crest is a sort of visual pun, it depicts an ox above a ford to symbolise the location. In 2008, a bronze statue of an ox was unveiled outside of what would have been the west stand. It was subsequently vandalised in January 2011, being covered in pink paint and the club used the opportunity to raise money for a breast cancer charity. The club mascot is, unsurprisingly, an ox called Ollie.
Ron Atkinson holds the club record for the most overall appearances for Oxford with 560. In total, nineteen players have made international appearances while playing for the club.
Since 2001, Oxford United have played at the Kassam Stadium, previously they played at the Manor Ground. The Kazzam Stadium hosted its first football match on 4 August 2001, it was a friendly match against a top team – Crystal Palace, which Oxford very luckily won on penalties following a 1–1 draw.
The all-seater stadium has a capacity of 12,500 and has only three stands instead of the usual four; when first planned in 1995 it was originally going to have a 16,000-seat capacity, but by the time the stadium opened Oxford was playing in a lower division, so the smaller capacity was deemed adequate.
The record attendance is 12,243, which was achieved in the final game of the 2005–06 season, when a defeat against Leyton Orient condemned them to relegation from the Football League. On Boxing Day 2006, a crowd of 11,065 watched United draw 0–0 with Woking at the Kassam Stadium, the largest-ever attendance for a Conference match (excluding play-offs). Although in June 2006, Sir Elton John played a concert to a crowd of around 16,500. In the event of an emergency the Kazzam Stadium would be used under emergency powers which exist under contingency plans for the partial evacuation of London so that might result in a record crowd.