[2][3] English side Saracens were the 2015–16 champions, having beaten Racing 92 of France in the 2016 final in Lyon.

[4][5] Twenty clubs from the three major European domestic and regional leagues competed in the Champions Cup.

The distribution of teams was: Due to the 2015 Rugby World Cup, it was decided that the play-off system that had previously decided the final team would be suspended, and that this year the winner of the 2015–16 European Rugby Challenge Cup would automatically qualify for the tournament.

Note: Placing shown in brackets, denotes standing at the end of the regular season for their respective leagues, with their end of season positioning shown through CH for Champions, RU for Runner-up, SF for losing Semi-finalist and QF for losing Quarter-finalist.

Teams will play each other twice, both at home and away, in the group stage, that will begin on weekend of 14/15/16 October 2016, and continue through to 20/21/22 January 2017, before the pool winners and three best runners-up progressed to the quarter-finals.

[12] In the event of a tie between two or more teams, the following tie-breakers will be used, as directed by EPCR: The eight qualifiers are ranked according to their performance in the pool stage and compete in the quarter-finals which were held on the weekend of 31 March, 1/2 April 2017.

In lieu of the draw that was used to determine the semi-final pairing, EPCR announced that a fixed semi-final bracket would be set in advance, and that the home team would be designated based on "performances by clubs during the pool stages as well as the achievement of a winning a quarter-final match away from home".