The 2005 UEFA Champions League final was the final match of the 2004–05 UEFA Champions League, Europe's primary club football competition. The showpiece event was contested between Milan of Italy and Liverpool of England at the Atatürk Olympic Stadium in Istanbul, Turkey on 25 May 2005. Liverpool, who had won the competition four times, were appearing in their sixth final, and their first since 1985. Milan, who had won the competition six times, were appearing in their second final in three years and tenth overall.

Each club needed to progress through the group stage and knockout rounds to reach the final, playing 12 matches in total. Liverpool finished second in their group behind 2004 runners-up Monaco and subsequently beat Bayer Leverkusen, Juventus and Chelsea to progress to the final. Milan won their group ahead of Barcelona and faced Manchester United, Inter Milan and PSV Eindhoven before reaching the final.

Milan were regarded as favourites before the match and took the lead within the first minute through captain Paolo Maldini. Milan striker Hernán Crespo added two more goals before half-time to make it 3–0. In the second half Liverpool launched a comeback and scored three goals in a dramatic six-minute spell to level the scores at 3–3, with goals from Steven Gerrard, Vladimír Šmicer and Xabi Alonso. The scores remained the same during extra time, and a penalty shoot-out was required to decide the champions. The score was 3–2 to Liverpool when Andriy Shevchenko's penalty was saved by Liverpool goalkeeper Jerzy Dudek. It was Liverpool's fifth European Cup, which meant they were awarded the trophy permanently and the right to wear a multiple-winner badge. Liverpool's comeback gave rise to the final being known as the Miracle of Istanbul, and is regarded as one of the greatest finals in the history of the tournament.

This was Liverpool's sixth final and it was their first appearance since the 1985 European Cup final, when they lost 1–0 to Juventus and were subsequently banned from European competition for six years due to the Heysel Stadium disaster. They had previously won the European Cup on four occasions in 1977, 1978, 1981 and 1984. The match was Milan's tenth appearance in the final. They had won on six occasions (1963, 1969, 1989, 1990, 1994, 2003), and lost three times (1958, 1993, 1995). In total the teams had participated in 14 finals between them. Prior to the game, Milan were assured of entering the Champions League the following season after finishing second in Serie A. Liverpool meanwhile had failed to finish in the top four in the Premier League, and had to win the final to enter the competition the following season. Even if they did win the match, they were not assured of a place after UEFA failed to confirm whether they would allow Liverpool to defend the championship. The Football Association supported Liverpool, stating, "We have already submitted a written request to have an additional place, should they win the Champions League". Milan manager Carlo Ancelotti said "I think a team that wins should have the right to defend it but we may just do the English federation a favour and solve this."

Milan were regarded as favourites and their team included many players who had experienced success in the competition. The most notable was captain Paolo Maldini, who had won the competition four times previously, all with Milan, and Clarence Seedorf who had won the competition three times with three clubs. Liverpool had been considered underdogs throughout the competition, but had beaten more favoured opposition, including Juventus and Chelsea, to reach the final. Liverpool manager Rafael Benítez acknowledged this: "Maybe Milan are favourites, but we have confidence, and we can win". Arsenal manager Arsène Wenger felt Liverpool would win the match: "I fancy Liverpool as Milan look jaded physically and certainly mentally, by losing the [Serie A] title, I think they have never had a better chance than now to beat Milan." Liverpool defender Jamie Carragher was not so optimistic, stating that the Liverpool side were not as good as the one that had won the 2001 UEFA Cup final: "No disrespect to the squad we have got now but it is obvious we are not as strong as we were when we won the UEFA Cup in 2001. Back then we had a settled team and that season when we went into games against Barcelona and Roma, we always felt we were as good as them."

The final was held at Atatürk Olympic Stadium, it was the first time a European final had been held in Turkey. There were reservations about holding the final in Turkey but UEFA chief executive, Lars-Christer Olsson was satisfied by the assurances of the Turkish authorities: "The conditions there are the same, generally, as for all countries and they have given guarantees, this is important, especially since their experiences last autumn. We have also asked for additional investments in the infrastructure around the stadium and they have agreed to this, too."

Teams qualified for the Champions League group stage, either directly or through three preliminary rounds, based on both their position in the preceding domestic league and the strength of that league. The competition proper started with the group stage, contested as eight double round-robin groups of four teams, with the top two qualifying for the knockout stages. The knockout stage ties from the round of 16 to the semi-finals were decided based on home and away matches.

Milan entered the competition in the group stage after winning Serie A. They won their group ahead of Barcelona and faced Manchester United, Inter Milan and PSV Eindhoven before reaching the final.