Brøndbyernes Idrætsforening, commonly known as Brøndby IF and occasionally referred to as Brøndby Copenhagen, was initially founded in 1964, as a result of a merger between two previously existing local sides. Since the club's formation, Brøndby have established themselves as one of Denmark's biggest and most successful clubs. Their main rivals are FC København. This rivalry is known as the New Firm, which is a reference to the Old Firm matches between Scottish clubs Rangers and Celtic.
The club's golden era is usually considered to have spanned the late 1980s and early 1990s, at a time when Brøndby dominated the domestic league, winning the title in 1985, 1987, 1988, 1990 and 1991. In addition, the club enjoyed success in the Danish Cup, lifting the trophy in 1988–89 and 1993–94. In amongst this period, the team also put in their best ever performances in continental competitions, reaching the quarter finals of the European Cup in 1986–87 and the semi-finals of the UEFA Cup in 1991.
In total, Brøndby have been crowned Danish champions on ten occasions and have been runners up nine times, which leaves them ranked as the second most successful club in Denmark. They have lifted the Danish Cup six times and the Danish League Cup twice. In 2006-07, they also won the Scandinavian Royal League competition for the first time.
Some of the greatest Danish players in history have represented Brøndby, including Michael Laudrup, Brian Laudrup, Peter Schmeichel, Dennis Rommedahl and Daniel Agger. Other notable footballers to play for the club include Johan Elmander and Kim Vilfort, who holds the side's all-time goalscoring record.
The team have played home matches at Brøndby Stadium since its opening in 1965. The stadium, which is sometimes known as Vilfort Park, underwent renovations between 1999 and 2000 and is currently able to hold a maximum of 29,000 spectators. Its record attendance was set at 31,508 for a match against København in 2003.