T21, originally T2 is a diesel-hydraulic locomotive operated by Swedish State Railways () 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 technically identical with the MaK 800D. The T21 was used to replace steam locomotives on branch lines. They were used until the 1990s.