Brøndby IF is a Danish professional football (soccer) club based in the town of Brøndby, on the western outskirts of Copenhagen. The club is also known as Brøndbyernes Idrætsforening, or Brøndby and BIF for short. The club, founded in 1964 as a merger between two local Brøndby clubs, has won 10 national Danish football championship titles and five national Danish Cups, since the club joined the Danish top-flight football league in 1981. Brøndby is the most successful Danish club on the European scene, with a UEFA Cup semi-final the best ever Danish result in the European competitions. Furthermore the club was the first Danish club to qualify for the UEFA Champions League, during the 1998-99 tournament.
Since the founding of fellow Copenhagen club F.C. Copenhagen in 1992, the two clubs have had a fierce rivalry, and the so-called "New Firm" games between the two sides attract the biggest crowds in Danish football. With F.C. Copenhagen, Brøndby has consistently formed a duo which have won eleven of the last sixteen Danish Superliga championships, and from 1995 to 2006, the club did not finish below second spot in the league.
Brøndby have always played their games at Brøndby Stadium. Through the first years in the secondary Danish leagues, the stadium was little more than a grass field with an athletics track circling the field of play. Following the first years of success in the highest Danish league, the athletic track was discarded and a further 2,000 seats were installed on top of concrete stands that were built from 1989 to 1990.