The draw for the group stage will be held on 24 August 2017, 18:00 CEST, at the Grimaldi Forum in Monaco.
The 32 teams are drawn into eight groups of four, with the restriction that teams from the same association cannot be drawn against each other. For the draw, the teams are seeded into four pots based on the following principles (introduced starting 2015–16 season):
Pot 1 contains the title holders and the champions of the top seven associations based on their 2016 UEFA country coefficients. As the title holders, Real Madrid, are one of the champions of the top seven associations, the champions of the association ranked eighth are also seeded into Pot 1 (regulations Article 13.05).
Pot 2, 3 and 4 contain the remaining teams, seeded based on their 2017 UEFA club coefficients.
In each group, teams play against each other home-and-away in a round-robin format. The group winners and runners-up advance to the round of 16, while the third-placed teams enter the 2017–18 UEFA Europa League round of 32. The matchdays are 12–13 September, 26–27 September, 17–18 October, 31 October – 1 November, 21–22 November, and 5–6 December 2017.
The youth teams of the clubs that qualify for the group stage also participate in the 2017–18 UEFA Youth League, where they are joined by the youth domestic champions of the top 32 associations.
A total of 32 teams play in the group stage: 22 teams which enter in this stage, and the 10 winners of the play-off round (5 from Champions Route, 5 from League Route). Qarabağ and RB Leipzig made their debut appearances in the group stage.
Seeding pot 1 (by association rank)[25]
Spain Real Madrid CC: 176.999
Germany Bayern Munich CC: 154.899
England Chelsea CC: 106.192
Italy Juventus CC: 140.666
Portugal Benfica CC: 111.866
France Monaco CC: 62.333
Russia Spartak Moscow CC: 18.606
Ukraine Shakhtar Donetsk CC: 87.526
Seeding pot 2
Spain Barcelona CC: 151.999
Spain Atlético Madrid CC: 142.999
France Paris Saint-Germain CC: 126.333
Germany Borussia Dortmund CC: 124.899
Spain Sevilla CC: 112.999
England Manchester City CC: 100.192
Portugal Porto CC: 98.866
England Manchester United CC: 95.192
Seeding pot 3
Italy Napoli CC: 88.666
England Tottenham Hotspur CC: 77.192
Switzerland Basel CC: 74.415
Greece Olympiacos CC: 64.580
Belgium Anderlecht CC: 58.480
England Liverpool CC: 56.142
Italy Roma CC: 53.666
Turkey Beşiktaş CC: 45.840
Seeding pot 4
Scotland Celtic CC: 42.785
Russia CSKA Moscow CC: 39.606
Portugal Sporting CP CC: 36.866
Cyprus APOEL CC: 26.210
Netherlands Feyenoord CC: 23.212
Slovenia Maribor CC: 21.125
Azerbaijan Qarabağ CC: 18.050
Germany RB Leipzig CC: 15.899
Note: UEFA club coefficient (CC) at the end of 2016–17 season, which is used for seeding, is listed in italics.