The 2020–21 UEFA Women's Champions League knockout phase began on 9 December 2020 with the round of 32 and ended with the final on 16 May 2021 at the Gamla Ullevi in Gothenburg, Sweden, to decide the champions of the 2020–21 UEFA Women's Champions League.

Below are the 32 teams that participated in the knockout phase (with their 2020 UEFA women's club coefficients, which took into account their performance in European competitions from 2015–16 to 2019–20 plus 33% of their association coefficient from the same time span).

The team that scored more goals on aggregate over the two legs advanced to the next round.

If away goals wre also equal, then extra time was played.

If no goals were scored during extra time, the tie was decided by a penalty shoot-out.

In the final, which was played as a single match, if the score was level at the end of normal time, extra time would be played, followed by a penalty shoot-out if the score remained tied.

[3] The 32 teams, including the 22 teams which received a bye and the ten winners of the second qualifying round, were seeded based on their UEFA women's club coefficients (the title holders were automatically seeded first).

The tie between Vålerenga and Brøndby was played as a single-leg match in Brøndby on 11 February 2021 due to the quarantine restrictions imposed by the relevant Norwegian authorities in response to the COVID-19 pandemic in Norway.

[7] The sixteen winners of the round of 32 were seeded based on their UEFA women's club coefficients (the title holders, should they qualify, were automatically seeded first).

[13][14] The eight winners of the round of 16, including the winner of the tie between Paris Saint-Germain and Sparta Prague whose identity was not known at the time of the draw, were drawn without any seeding or restrictions, with the first team drawn in each tie to be the home team of the first leg.

[13] The four quarter-final winners, whose identity was not known at the time of the draw, were drawn without any seeding or restrictions, with the first team drawn in each tie to be the home team of the first leg.

[19] A draw was held on 12 March 2021, 12:00 CET (after the quarter-final and semi-final draws), to determine which semi-final winner would be designated as the "home" team for administrative purposes.