The 46 AFC member associations (excluding the associate member Northern Mariana Islands) are ranked based on their national team's and clubs' performance over the last four years in AFC competitions, with the allocation of slots for the 2019 and 2020 editions of the AFC club competitions determined by the 2017 AFC rankings (Entry Manual Article 2.3):
In each region, there are four groups in the group stage, including a total of 12 direct slots, with the 4 remaining slots filled through play-offs.
The top 12 associations in each region as per the AFC rankings are eligible to enter the AFC Champions League, as long as they fulfill the AFC Champions League criteria.
The top six associations in each region get at least one direct slot in the group stage, while the remaining associations get only play-off slots (as well as AFC Cup group stage slots):
The associations ranked 1st and 2nd each get three direct slots and one play-off slot.
The associations ranked 3rd and 4th each get two direct slots and two play-off slots.
The associations ranked 5th each get one direct slot and two play-off slots.
The associations ranked 6th each get one direct slot and one play-off slot.
The associations ranked 7th to 12th each get one play-off slot.
The maximum number of slots for each association is one-third of the total number of eligible teams in the top division.
If any association gives up its direct slots, they are redistributed to the highest eligible association, with each association limited to a maximum of three direct slots.
If any association gives up its play-off slots, they are annulled and not redistributed to any other association.
For the 2019 AFC Champions League, the associations are allocated slots according to their association ranking which was published on 15 December 2017, which takes into account their performance in the AFC Champions League and the AFC Cup, as well as their national team's FIFA World Rankings, during the period between 2014 and 2017.
Participation for 2019 AFC Champions League
NOTE: The following slot allocation is provisional, assuming that all eligible associations enter the allocated number of teams based on the entry manual. The final slot allocation will be confirmed by the AFC by November 2018, based on the list of teams passing the club licensing requirements.
NOTE: The following list of participating teams is provisional. The final list of participating teams will be confirmed by the AFC by November 2018, based on the slot allocation finalised by the AFC Competitions Committee and the list of teams passing the club licensing requirements.
In the following table, the number of appearances and last appearance count only those since the 2002–03 season (including qualifying rounds), when the competition was rebranded as the AFC Champions League. Only teams assured of a place are displayed.
In the qualifying play-offs, each tie is played as a single match. Extra time and penalty shoot-out are used to decide the winner if necessary (Regulations Article 9.2). The eight winners of the play-off round advance to the group stage to join the 24 direct entrants. All losers in each round from associations with only play-off slots enter the AFC Cup group stage.
The bracket of the qualifying play-offs for each region will be officially announced by the AFC prior to the group stage draw on 22 November 2018, and is determined based on the association ranking of each team, with the team from the higher-ranked association hosting the match. Teams from the same association cannot be placed into the same play-off.
The draw for the group stage will be held in 22 November 2018, 16:30 MYT (UTC+8), at the AFC House in Kuala Lumpur, Malaysia. The 32 teams are drawn into eight groups of four: four groups each in the West Region (Groups A–D) and the East Region (Groups E–H). Teams from the same association cannot be drawn into the same group.
Goals scored in head-to-head matches among tied teams;
Away goals scored in head-to-head matches among tied teams;
If more than two teams are tied, and after applying all head-to-head criteria above, a subset of teams are still tied, all head-to-head criteria above are reapplied exclusively to this subset of teams;
Goal difference in all group matches;
Goals scored in all group matches;
Penalty shoot-out if only two teams are tied and they met in the last round of the group;
Disciplinary points (yellow card = 1 point, red card as a result of two yellow cards = 3 points, direct red card = 3 points, yellow card followed by direct red card = 4 points);
In the round of 16, the winners of one group play the runners-up of another group from the same region, with the group winners hosting the second leg, and the matchups determined by the group stage draw.
In the quarter-finals, the four teams from the West Region play in two ties, and the four teams from the East Region play in two ties, with the matchups and order of legs decided by draw, without any seeding or country protection.
In the semi-finals, the two quarter-final winners from the West Region play each other, and the two quarter-final winners from the East Region play each other, with the order of legs determined by the quarter-final draw.
In the final, the two semi-final winners play each other, with the order of legs (first leg hosted by team from the West Region, second leg hosted by team from the East Region) reversed from the previous season's final.