The 1988–89 season of the European Cup football club tournament was won for the first time since 1969, and third time overall, by Milan comfortably in the final against former winners Steaua București. It was one of the most one-sided final since the replayed final in 1974.^{[citation needed]}

PSV, the defending champions, were eliminated by Real Madrid in the quarter-finals.

¹ Club Brugge progressed to the Second round on away goals.

² Neuchâtel Xamax progressed to the Second round after winning a penalty shoot-out.

Porto beat HJK 3–2 on aggregate.

Górnik Zabrze beat Jeunesse Esch 7–1 on aggregate.

Real Madrid beat Moss 4–0 on aggregate.

Celtic beat Budapest Honvéd 4–1 on aggregate.

Werder Bremen beat Dynamo Berlin 5–3 on aggregate.

Milan beat Vitosha 7–2 on aggregate.

Red Star Belgrade beat Dundalk 8–0 on aggregate.

17 Nëntori Tirana beat Ħamrun Spartans 3–2 on aggregate.

IFK Göteborg beat Pezoporikos Larnaca 7–2 on aggregate.

Steaua Bucureşti beat AC Sparta Prague 7–3 on aggregate.

Spartak Moscow beat Glentoran 3–1 on aggregate.

The UEFA Champions League /juːˈeɪfə ˈtʃæmpiənz ˈliːɡ/ known simply as the Champions League and originally known as the European Champion Clubs' Cup or European Cup, is an annual continental club football competition organised by the Union of European Football Associations (UEFA) since 1955 for the top football clubs in Europe. It is one of the most prestigious tournaments in the world and the most prestigious club competition in European football. The final of the competition is the most watched annual sporting event worldwide, drawing over 300 million television viewers.

Prior to 1992, the tournament was officially called the "European Champion Clubs' Cup," but was usually referred to simply as the "European Cup." The competition was initially a straight knockout competition open only to the champion club of each country. During the 1990s, the tournament began to be expanded, incorporating a round-robin group phase and more teams. Europe's strongest national leagues now provide up to four teams each for the competition. The UEFA Champions League should not be confused with the UEFA Europa League, formerly known as the UEFA Cup.