The Audi A6 is an executive luxury car produced by the German automaker Audi. It is available in saloon and estate (Avant) body styles. The second and third generation A6 were also used as the basis for the Audi allroad quattro and A6 allroad quattro models respectively.

Competitors to the A6 include the Lexus GS, BMW 5 Series, Mercedes-Benz E-Class, and Cadillac STS.[citation needed]

Audi's mid-size car was named the Audi 100 (or Audi 5000 in the United States) and was released in three successive generations (C1, C2 and C3). In 1994, the latest generation (C4) of the Audi 100 was facelifted and re-badged as the A6, to fit in with Audi's new alphanumeric nomenclature (as the full-size A8 had just been introduced). The exterior was changed only slightly from the "C4" Audi 100 - new front and back lights, new radiator grid, similarly with chassis and engine and transmission choices. The UK was the first market to receive the A6, as stock of right-hand-drive Audi 100s had run out before expected, and before the rest of Europe.

The new engines for the A6 were 1.8 20V I4, 2.8 30V, 1.9 TDI I4, and the 2.5 TDI I5 (140 PS), with the 2.3L I5 engine being dropped on most markets. The S6's 4.2 V8 engine was uprated to 290PS (286hp/213kW) and a new 326PS (322hp/240kW) version was added (S6+ made by quattro GmbH).