Draw
The draw for the group stage was held on 6 December 2017, 14:00 MYT (UTC+8), at the AFC House in Kuala Lumpur, Malaysia. [3] [4] The 36 teams were drawn into nine groups of four: three groups each in the West Asia Zone (Groups A–C) and the ASEAN Zone (Groups F–H), and one group each in the Central Asia Zone (Group D), the South Asia Zone (Group E), and the East Asia Zone (Group I). Teams from the same association in the West Asia Zone and ASEAN Zone could not be drawn into the same group.
The seeding of each team in the draw was determined by their association and their qualifying position within their association. The mechanism of the draw was as follows:
- For the West Asia Zone, a draw was held for the five associations with two direct entrants (Iraq, Syria, Jordan, Bahrain, Lebanon) to determine the three associations occupying seeds 1 and 2, with seeds 1 placed in order for Groups A, B and C, and the two associations occupying seeds 3 and 4, with seeds 3 placed in order for Groups A and B. The remaining teams were then allocated to groups according to the rules set by AFC.
- For the ASEAN Zone, a draw was held for the five associations with two direct entrants (Vietnam, Indonesia, Myanmar, Philippines, Singapore) to determine the three associations occupying seeds 1 and 2, with seeds 1 placed in order for Groups F, G and H, and the two associations occupying seeds 3 and 4, with seeds 3 placed in Groups F and G. The remaining teams were then allocated to the groups according to the rules set by AFC.
- For the Central Asia Zone, the South Asia Zone, and the East Asia Zone, no draw was held, and the teams were allocated to the groups according to their association ranking published on 30 November 2016.
The following 36 teams entered into the group-stage draw, which included the 31 direct entrants and the five winners of the play-off round of the qualifying play-offs, whose identity was not known at the time of the draw.
| Zone | Groups | Seed 1 | Seed 2 | Seed 3 | Seed 4 |
|---|---|---|---|---|---|
| West Asia Zone | A–C |  Malkiya [note 1] | Manama [note 1] |  Al-Quwa Al-Jawiya [note 1] | Al-Zawraa [note 1] |
 Al-Ahed [note 1] | Al-Ansar [note 1] |  Al-Jaish [note 1] | Al-Wahda [note 1] | ||
 Al-Faisaly [note 1] | Al-Jazeera [note 1] |  Dhofar | Al-Suwaiq (Play-off West Asia) | ||
| Central Asia Zone | D |  Istiklol |  Altyn Asyr [note 2] |  Alay Osh | Ahal (Play-off Central Asia) |
| South Asia Zone | E |  Aizawl |  New Radiant |  Abahani Limited Dhaka [note 2] | Bengaluru (Play-off South Asia) |
| ASEAN Zone | F–H |  Ceres–Negros [note 2] [note 3] | Global Cebu [note 2] [note 3] |  Shan United [note 3] | Yangon United [note 3] |
 Bali United [note 3] | Persija Jakarta [note 3] |  FLC Thanh Hóa [note 3] | Sông Lam Nghệ An [note 3] | ||
 Tampines Rovers [note 3] | Home United [note 3] |  Johor Darul Ta'zim |  Boeung Ket Angkor (Play-off ASEAN) | ||
| East Asia Zone | I |  April 25 |  Hang Yuen |  Benfica de Macau | Hwaebul (Play-off East Asia) |
- Standby teams [note 4]
-
Al-Wehdat (for Al-Faisaly) -
Mohun Bagan (for Aizawl) -
Hà Nội (for FLC Thanh Hóa) -
Selangor (for Johor Darul Ta'zim) -
Madura United (for Bali United) -
Yadanarbon (for Shan United) -
Meralco Manila (for Ceres–Negros)[note 2] [note 5] -
Geylang International (for Tampines Rovers)
