The Mälaren Line (Swedish: Mälarbanan) is a railway line from Stockholm via Västerås to Örebro in Sweden.

The section from Stockholm to Kolbäck and from Valskog to Arboga has double track.

The line was upgraded to high-speed in 2005.

[1] It takes its name from lake Mälaren, along the northern edge of which the railway runs.

The Stockholm commuter rail system uses the tracks east of Bålsta, in addition to the intercity trains.