The 2018 AFC Champions League qualifying play-offs were played from 16 to 30 January 2018. A total of 22 teams competed in the qualifying play-offs to decide eight of the 32 places in the group stage of the 2018 AFC Champions League.
The following 22 teams, split into two regions (West Region and East Region), entered the qualifying play-offs, consisting of three rounds:
<section begin=Format /> In the qualifying play-offs, each tie was played as a single match. Extra time and penalty shoot-out were used to decide the winner if necessary (Regulations Article 9.2). The eight winners of the play-off round advanced to the group stage to join the 24 direct entrants. All losers in each round from associations with only play-off slots entered the AFC Cup group stage.<section end=Format />
The schedule of each round was as follows.
<section begin=Bracket /> The bracket of the qualifying play-offs for each region was determined by the AFC based on the association ranking of each team, with the team from the higher-ranked association hosting the match. Teams from the same association could not be placed into the same play-off.<section end=Bracket />
A total of four teams played in the preliminary round 1. <section begin=Preliminary round 1 />
|+East Region
<section end=Preliminary round 1 />
A total of eight teams played in the preliminary round 2: six teams which entered in this round, and two winners of the preliminary round 1. <section begin=Preliminary round 2 />
|+East Region
<section end=Preliminary round 2 />
A total of 16 teams played in the play-off round: twelve teams which entered in this round, and four winners of the preliminary round 2. <section begin=Play-off round />
|+West Region
|+East Region
<section end=Play-off round />