The Audi A4 is a series of compact executive cars produced since 1994 by the German car manufacturer Audi AG, a subsidiary of the Volkswagen Group that has been built in five generations.

The first generation of Audi A4 debuted in October 1994, commonly referred to as B5 and it was designed by Imre Hasanić (1991) and Jürgen Albamonte (1992). It is made of the freshly developed Volkswagen PL45 (B5) platform, which allowed longitudinal-mounted engines, front or all-wheel drive. In order to make the weight balance, the engine was installed on the front axle. The clear-lenses headlights were new for the compact-sedan built by Audi. A ranked A-pillar and rounded greenhouse makes the car look sleek. In the back, unlike the last 80 model, the trunk was ends with a sharp line.

On the inside, the modern interior design greeted its owners with appealing shapes, rich textures and polished walnut trim for specific trim levels. The seats had ample bolstering that was designed for good support during hard cornering. Under the hood, the 1994 A4 had the newest engines, the 1.8-liter unit with 5-valves per cylinder was installed and offered a good balance between fuel-efficiency and performance. The 5 or 6 Speed manual transmission was standard depending on the engine.

The latest generation of the Audi A4 was introduced in June 2015, the official launch took place at the Frankfurt Motor Show in September 2015. The exterior of the new generation was designed by Frank Rimili while the interior was a creation of Rüdiger Müller. This is the fifth generation of the Audi A4 and it was commonly referred to as the B9. Unlike most of its previous models, this model got major mid-cycle facelift, including a refurbished exterior and interior design and technical upgrades.

The exterior design was more unified with the latest evolution of Audi's design language by making a small but wide-spread leap. On the outside, the Singleframe grille is flatter which gives a wider look, with more horizontal lines that emphasize the car's width being present on both the ends. Revamped contour lines above the wheels make for a fresher side view as well. The new headlights use LED technology as standard, although the Matrix LED headlamps are still optional.

On the powerplant side, the facelifted fifth-generation A4 feature three choices that include a mild-hybrid system based on 12 volts. In total, six engine options are available with either front-wheel-drive or quattro all-wheel-drive, of which some are paired with a manual transmission, a seven-speed S Tronic or an eight-speed Tiptronic. Audi claims that even though the new A4 is slightly larger in size as compared to its predecessor, it is also 120kg lighter. For 2021, Audi's Quattro all-wheel-drive powertrain is a standard equipment, as are lane departure warning and wireless Apple CarPlay.