The 30-year-old former Wales international has made five appearances for the Baggies this season, four of which have come from the bench.
He has scored nine goals in 99 games since moving to The Hawthorns from Reading in August 2016.
“It remains a real pleasure to represent this club,” he said.
Robson-Kanu retired from international football in August 2018 after winning 44 caps and scoring five goals, two of them at Euro 2016.
Notify me of follow-up comments by email.
Notify me of new posts by email.