Dm and Dm3 is a series of locomotives used by Swedish State Railways (Swedish: Statens Järnvägar, SJ) and later Malmtafik i Kiruna (MTAS) for pulling iron ore trains on the Iron Ore Line in Sweden and Ofoten Line in Norway.

As initially developed, the twin-section Dm class locomotives were capable of pulling 3,400 tonne trains.

Rather than copy its neighbour, the Norwegian State Railway chose to build a different and more powerful locomotive, the NSB El 15 to modernise its operations around the same time.

[2] With further increases in train size, MTAB decided to order new locomotives to replace the older Dm2 and Dm3 units.

[4] In 2004 one set was donated to the heritage society Malmbanans Vänner, who also own one of the similar-design Norwegian El 12 class locomotives as used on the Iron Ore Railway.