The fourth round of AFC matches for 2018 FIFA World Cup qualification was played from 5 to 10 October 2017.
[1] The winners advanced to the inter-confederation play-offs against the fourth-placed team from the CONCACAF fifth round.
[3] The order of legs was pre-determined by the AFC, announced during the draw for the third round.
The third-placed team from Group A hosted the first leg, and the third-placed team from Group B hosted the second leg.
[4] Australia won 3–2 on aggregate and advanced to the inter-confederation play-offs.