T21, originally T2 is a diesel-hydraulic locomotive operated by Swedish State Railways (Swedish: Statens Järnvägar, SJ) and Nora Bergslags Järnväg (NBJ) of Sweden.

60 units were built during the 1950s by Maschinenbau Kiel and Svenska Järnvägsverkstäderna based on the German DB Class V65.

The T21 was used to replace steam locomotives on branch lines.

The order consisted of 56 locomotives, of which ten were to be built in Sweden with a Swedish hydraulic shift, designated T3, later T22.

This diesel locomotive-related article is a stub.