The third generation Mazda6 sedan was unveiled during Moscow International Automobile Salon on 29 August 2012, and the station wagon version followed during the 2012 Paris Motor Show in the following month. In this generation, there are only 4-door sedan and 5-door station wagon versions available.[38] The design was previewed by both the Takeri concept, unveiled at the 2011 Tokyo Motor Show, and the Shinari concept from 2010.

The design was a finalist in the "2013 World Design of the Year"

The Mazda6 was second place in the 2003 European Car of the Year awards and made Car and Driver magazine's Ten Best list for 2003. The Sport Wagon won the Canadian Car of the Year Best New Station Wagon award, while the Sport sedan won the Canadian Car of the Year Best New Family Car award for 2005. The Atenza Wagon also won What Car?'s Best Estate award in 2004. Also the Mazda6 won the 2003 Semperit Irish Car of the Year.

The Mazda6 won the 'Best Mid-size Car (over $28,000)' title in Australia's Best Cars in 2002 and 2003. It came second in 2004, behind the Subaru Liberty, and fifth in 2005 (the Honda Accord Euro was first in 2005). Wheels magazine also awarded the Mazda6 winner of its Active Safety Program in July 2005. In December 2007 the Mazda6 won the Carsales Peoples Choice award for its class in Australia.

The Mazda6 also won "Best Family Sedan" in MotorWeek's 2009 Driver's Choice Awards.

The Mazda6 was praised for its edgy handsome design, communicative steering, and tight suspension. However, as it was designed as a world car in order to fit the needs of Europe and Japan, it was smaller than its North American contemporaries in the midsize segment, being criticized for its reduced passenger space. Its acceleration, particularly the V6 engine models, lagged behind that of its rivals as well.

The hatchback's liftback/notchback styling was considered a clever design to disguise it as a four-door saloon, as North Americans generally considered trunks more elegant than hatches. The estate had an early demise, but the hatchback was somewhat successful in Canada, especially in Québec, though it would not have a 2009 refresh, as both models were unpopular in the US.

Motorsport
For the 2013 Rolex Sports Car Series the Mazda6 was involved in the short lived Grand-Am GX series. Three cars were used, one racing under the number #70, being driven by Jonathan Bomarito, Marino Franchitti, Tom Long, Sylvain Tremblay, and James Hinchcliff, a VisitFlorida.com sponsored car using the number #00, driven by Tristan Nunez, Spencer Pigot, and Tristan Vautier, and Yojiro Terada, and the third car was driven under the #25, being driven by Andrew Carbonell, Tom Long, Rhett O’Doski, and Derek Whitis. The car was successful, albeit in a class with few other cars. The class they were driven in was the GX class, intended for cars using alternative fuels or alternative technologies. The class folded after one year, and was not carried onto the 2014 United SportsCar Championship