The Mazda RX-8 is a car manufactured by Mazda Motor Corporation which first appeared in North America at the North American International Auto Show in 2001. The vehicle features a 250 PS JIS (184 kW, 247 hp) @8500rpm (238 SAE net hp for North America) RENESIS Wankel rotary engine, which won International Engine of the Year and Best New Engine awards in 2003 and holds the "2.5 to 3 liter" size award for 2003 and 2004. The engine redlines at 9000 rpm, and cuts off fuel at 9500 rpm. As of March 31, 2005, 114,444 RX-8 models had been sold worldwide since introduction.

The RX-8 was also Wheels magazine's Car of the Year for 2003 and was on Car and Driver magazine's Ten Best list for 2004 and 2005. It was nominated for the North American Car of the Year award for 2004 as well.

One major change in design between the RX-8 and the RX-7 is the addition of a pair of rear-hinged ('suicide') half-doors (similar to the 3rd door in the Saturn coupe), which allow easier access to the two back seats. The RX-8 has no center pillars separating the front and rear doors. The front doors are hinged at the front, and aluminum back doors are hinged at the rear. Because of the overlapped design, the rear doors can only be opened when the front doors are open.

Weight distribution in the RX-8 is a balanced 50/50 in the front and rear. Mazda achieved this by pushing the engine back past the front axle, achieving a Front-midships engine layout.

Mazda’s new Renesis rotary engine is smaller and lighter than prior rotaries, primarily due to the lack of a turbocharger and associated parts. New to its design are a side-intake and side-exhaust. The engine produces 210 PS (155 kW) in the automatic transmission form, and 250 PS (184 kW) in the manual transmission form. Mazda does, however, plan on eventually releasing a Mazdaspeed variant of the RX-8 with a different front facia, upgraded handling, and perhaps a supercharger.

Mazda aggressively trimmed mass from the RX-8 concept by using aluminium and plastic for body panels and installing a carbon composite driveshaft. The dimensions of the RX-8 are virtually identical to those of the Porsche 911 Carrera.

According to Mazda, the RX-8's RENESIS engine was originally developed to potentially use either gasoline or hydrogen as fuel. Mazda does have a hydrogen-fueled RX-8 prototype it tests at its headquarters.

The car is used in the Formula Woman racing series which started in 2004. A slightly modified RX-8 was also featured in the 2003 film X2: X-Men United.