Mundijong is an outer suburb of the Western Australian capital city of Perth. Originally named Jarrahdale Junction, it was at the junction of the Jarrahdale to Rockingham railway line and the government railway line from Perth to Bunbury, which was built in 1893. At the 2016 census, Mundijong had a population of 1,232. A town grew up around the junction, and a timber depot, which included a large planing mill, was constructed.