Chelsea defeated Manchester City 1–0 in the final, which was played at the Estádio do Dragão in Porto, Portugal, for their second European Cup title.

The Atatürk Olympic Stadium in Istanbul, Turkey, was originally appointed to host the 2020 UEFA Champions League Final, but it was moved due to the COVID-19 pandemic in Europe to the Estádio da Luz in Lisbon.

[6] Bayern Munich were the defending champions, but they were eliminated in the quarter-finals by Paris Saint-Germain, whom they had beaten in the previous year's final.

[9] Apart from the allocation based on the country coefficients, associations may have additional teams participating in the Champions League, as noted below: The following is the access list for this season.

UEFA used "adaptive re-balancing" to change the access list once the berths for the Champions League and Europa League title holders were determined, and rounds which had already been drawn or played by the time the title holders were determined would not be impacted (Regulations Article 3.04).

[8] The following changes were made: In early April 2020, UEFA announced that due to the COVID-19 pandemic in Europe, the deadline for entering the tournament had been postponed until further notice.

[11] UEFA also sent a letter to all member associations that domestic leagues must be completed in full without ending prematurely in order to qualify for European competitions.

A suspended domestic competition may also be restarted with a different format from the original one in a manner which would still facilitate qualification on sporting merit.

Notes The schedule of the competition was as follows (all draws were held at the UEFA headquarters in Nyon, Switzerland unless otherwise stated).

The original schedule of the competition, as planned before the pandemic, was as follows (all draws were to be held at the UEFA headquarters in Nyon, Switzerland, unless stated otherwise).

The major revision to schedule of the competition, as planned before relocation the final from Istanbul, was as follows (all draws were to be held at the UEFA headquarters in Nyon, Switzerland, unless stated otherwise).

Due to the COVID-19 pandemic in Europe, the following special rules were applicable to the competition:[45][46] On 24 September 2020, UEFA announced that five substitutions would be permitted from the group stage onward, with a sixth allowed in extra time.

[5] However, on 13 May 2021 UEFA announced that the final would be relocated to Porto in order to allow fans to attend the match.

From the ten losers of Champions Path, two teams, Tirana and Ludogorets Razgrad, determined by a draw held on 31 August 2020 after the Europa League second qualifying round draw,[55] entered the 2020–21 UEFA Europa League play-off round (Champions Path), while the other eight teams entered the 2020–21 UEFA Europa League third qualifying round (Champions Path).

[62] İstanbul Başakşehir, Krasnodar, Midtjylland and Rennes made their debut appearances in the group stage.

In the knockout phase, teams played against each other over two legs on a home-and-away basis, except for the one-match final.

[70] The award winners were announced and presented during the 2021–22 UEFA Champions League group stage draw in Turkey on 26 August 2021.