The Mazda Atenza or Mazda 6 is a mid-size car produced by the Japanese car manufacturer Mazda since 2002. The name Atenza is used only in Japan with the Mazda 6 moniker used everywhere else in the world. The Atenza/Mazda 6 replaced the Capella/626, and has sold over one million units worldwide since its introduction, hitting that sales milestone faster than previous Mazda.

The Mazda Atenza was the first of the new generation of 'Stylish', 'Insightful', and 'Spirited' range from Mazda. It was followed by the Mazda 2 in December 2002, RX-8 in August 2003, Mazda3 in January 2004, MX-5 in October 2005, and Mazda CX-7 in November 2006.

The Mazda Atenza is currently raced in the SCCAPro Racing Speed World Challenge Touring Car Series. Mazda finished first in the manufacturer's championship standings. Mazda Atenza/6 drivers also finished first and second in the Touring Car driver points.

First generation (2002–2007)

The model lineup consists of a four-door sedan, a five-door liftback and a five-door station wagon, marketed in North America as the "Sport Sedan", "5-Door" and "Sport Wagon". In Australia, the lineup starts with Limited, available only as a sedan. Then comes the Classic, available in sedan, hatch or wagon. The Luxury model is next available in sedan and hatch versions. Topping the range is the Luxury Sports model, available only as a hatch. When it arrived in North America, it was first sold as a 2003 model in the United States and as a 2004 model in Canada. In Europe, the luxury sports model was available as a direct injection turbodiesel ("DITD") station wagon up until 2007. As of 2008, the European Mazda catalog lists only the "Sport" version of the turbodiesel station wagon, while the "Luxury Sport" version has been dropped.

Drivetrain combinations include the Mazda MZR engine in configurations of 1.8 L(L8 European Model), 2.0 L(LF European Model) and 2.3 L(L3 European Model), initially with a five-speed manual or four-speed automatic transmission (with sequential-automatic option, dubbed the "Four-Speed Sport AT"). In the US domestic market a 3.0 L Duratec 30 V6 engine is also available with a five-speed manual or five-speed automatic (with sequential-automatic option, dubbed the "5-Speed Sport AT"). European and Australian versions also feature a four-cylinder turbodiesel that comes with a six-speed manual transmission and produces significantly more torque than the V6 with much improved fuel economy.

In North America, the 5-speed automatic optional on the V6 models is replaced by a 6-speed automatic from Ford for 2005 model year. The four-cylinder model receives a five-speed automatic in the following year. Power is directed to the front wheels only in most markets, although full-time all wheel drive models are available in Japan, Europe and Australia. Not all configurations are available in all areas - for example, the Mazda 6 as released in Australia is available in 2.3L four-cylinder guise only, while the 626 which it replaced was available with a choice of four or six-cylinder engines. This was due to the Australian Mazda6 being sourced from Japan where the V6 engine was not available. The Duratec 30 V6 engine fitted to vehicles manufactured at Flat Rock, Michigan is only available in the US and Canadian domestic markets.