The 1998–99 UEFA Champions League was the 44th season of the UEFA Champions League, Europe's premier club football tournament, and the seventh since it was renamed from the "European Champion Clubs' Cup" or "European Cup". The competition was won by Manchester United, coming back from a goal down in the last two minutes of injury time to defeat Bayern Munich 2–1 in the final. Teddy Sheringham and Ole Gunnar Solskjær scored United's goals after Bayern had hit the post and the bar. They were the first English club to win Europe's premier club football tournament since 1984 and were also the first English club to reach a Champions League final since the Heysel Stadium disaster and the subsequent banning of English clubs from all UEFA competitions between 1985 and 1990.
Manchester United also completed the Treble, becoming the fourth side in Europe to do so and in the process preventing Bayern Munich from achieving the feat themselves, Bayern eventually finished runners-up in their domestic cup two weeks later.
The Red Devils won the trophy without losing a single game, despite having competed in a group with Bayern Munich, Barcelona and Brøndby plus two highly rated Italian clubs in the knock-out stages. However, United became champions with just five wins in total, the lowest number of wins recorded by a champion in the Champions League era to date, though the competition now has an extra round of two games in the knock-out stages.
It was the first time that a team that had not won their domestic league the previous season won the Champions League and it was also the first time that Europe's top honour was won by a team who would not have qualified for the tournament under the old qualification rules (title holder or national league champion). For the second time, the runners-up of eight domestic leagues (three teams from Spain (including current UEFA Champions League title holder); two teams from England, France, Greece (replacing Turkey), Holland, Germany, Italy and Portugal) were entered into the competition. The runners-up entered the second qualifying round while the league winners entered directly the group stage (except for Greece where both winner and runner-up entered the second qualifying).
56 teams entered the competition: the national champions of each of the top 48 nations in the UEFA coefficient rankings (except Liechtenstein), plus the runners-up from each of the top eight nations and UEFA Champions League holders, Real Madrid. The national champions of the associations ranked 1–7 (Italy, Germany, Spain, France, Netherlands, England and Portugal), plus the title holders, all received a bye to the group stage, while the national champions of the associations ranked 8–15 (Greece, Czech Republic, Norway, Austria, Russia, Croatia, Turkey and Denmark) and the runners-up of the associations ranked 1–8 all entered in the second qualifying round. The remaining national champions from the associations ranked 16–48 entered in the first qualifying round.