2018 FIFA World Cup qualification – AFC fourth round

The fourth round of AFC matches for 2018 FIFA World Cup qualification was played from 5 to 10 October 2017. The winners advanced to the inter-confederation play-offs against the fourth-placed team from the CONCACAF fifth round.

Format
In the fourth round, the third-placed teams from the two third round groups competed in a two-legged home-and-away play-off.

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.

Matches
Australia won 3–2 on aggregate and advanced to the inter-confederation play-offs.