The DB Class 66 (German: Baureihe 66) was a class of two Deutsche Bundesbahn (DB) locomotives designed for fast goods train and passenger train services on the main and branch lines of Deutsche Bundesbahn (DB), the national railway of the former West Germany.

The 66s had a top speed of 100 km/h and an axle load of only 15 tonnes which made them ideally suited to such duties.

However increasing competition from diesel locomotives meant that no more engines were built after the two prototypes, even though they fully met all expectations and were a very successful design.

Because great emphasis was placed on the working conditions for the engine driver and stoker, the Class 66 had a fully enclosed driver's cab, skylights, floor heating and upholstered seats with back rests.

From autumn 1967 both engines were fitted equipment for working push-pull services.