The AFC Competitions Committee proposed a revamp of the AFC club competitions on 25 January 2014, which was ratified by the AFC Executive Committee on 16 April 2014. The 46 AFC member associations 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 2017 and 2018 editions of the AFC club competitions determined by the 2016 AFC rankings :
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 :
*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 2017 AFC Champions League, the associations were allocated slots according to their association ranking published on 30 November 2016, 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 2013 and 2016. The slot allocation was announced on 7 December 2016, with India and Maldives returning to the West Region. The final slot allocation, after unused slots were redistributed, was announced on 12 December 2016. ;Notes
Teams
The following 47 teams from 19 associations entered the competition. In the following table, the number of appearances and last appearance count only those since the 2002–03 season, when the competition was rebranded as the AFC Champions League. ;Notes
Schedule
The schedule of the competition was as follows. Starting from 2017, matches in the West Region were played on Mondays and Tuesdays instead of Tuesdays and Wednesdays.
