[1] The competition got underway on the weekend of 17 October 2014 with the first round of the pool stage, and ended with the final on 2 May 2015 at Twickenham Stadium, London, England.

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.

For the purpose of creating the tiers, Aviva Premiership clubs were ranked only according to their finishing positions in the League table, and not based on performance in the knockout phase of the season, while Top 14 and Pro12 clubs were ranked based on their League performances and on their qualification for the knockout phases of their championships, so a losing quarter-finalist in the Top 14 would be seeded below a losing semi-finalist, even if they finished above them in the regular season.

Teams played each other twice, both at home and away, in the group stage, that began on the weekend of 17/18/19 October 2014, and continued through to 23/24/25 January 2015, before the pool winners and three best runners-up progressed to the quarter-finals.

[13] In the event of a tie between two or more teams, the following tie-breakers were used, as directed by EPCR: The eight qualifiers were seeded according to performance in the pool stage, and competed in the quarter-finals, which were held on the weekend of 3–5 April 2015.