Turbo-diesel, also written as turbodiesel and turbo diesel refers to any diesel engine equipped with a turbocharger. Turbocharging is common in modern car and truck diesel engines to produce higher power outputs, lower emissions levels, improved efficiency from a similar capacity of engine. Turbo-diesels in automobiles offer a higher refinement levels than their naturally aspirated counterparts.

The turbocharger was invented in the early 20th century by Alfred Büchi, a Swiss engineer and the head of diesel engine research at Gebruder Sulzer engine manufacturing company in Winterthur. Büchi specifically intended his device to be used on diesel engines. His patent of 1905 noted the efficiency improvements that a turbocharger could bring to diesel engines which in 1922 had first been developed for use in road transportation.

At the time metal and bearing technology was not sufficiently advanced to allow a practical turbocharger to be built. The first practical turbodiesels were marine engines fitted to two German passenger liners- the Danzig and the Preussen in 1923, each having two 10-cylinder engines of 2,500 horsepower (the naturally aspirated versions of the same engine produced 1,750 HP). By the late 1920s several diesel engine builders were making large turbodiesels for marine and stationary use such as Sulzer Bros., MAN, Daimler-Benz and Paxman.