The Joondalup line is a commuter rail service in Western Australia, linking the Perth central business district (CBD) with the metropolitan area's north-western suburbs. The service is operated on the Northern Suburbs Railway by Transperth Train Operations, a division of the Public Transport Authority, and is part of the Transperth network. It is 40.7 kilometres (25.3 mi) long and serves 13 stations. The service is currently being extended to Yanchep.

Railways in Perth, the capital city of Western Australia, have existed since 1881, when the Eastern Railway was opened between Fremantle and Guildford. Today, Perth has seven Transperth commuter rail lines and 75 stations.