The SLS AMG GT3 was developed from the SLS AMG Coupé, which was introduced at the 2009 Frankfurt Motor Show as the first sports car built entirely by Mercedes-AMG. The racing programme began testing at Lausitz Eurospeedway in June 2010, with the car officially introduced at the 2010 New York International Auto Show. FIA homologation under GT3 regulations was secured in time for deliveries beginning in February 2011. A total of 86 cars were sold over the car's production life.
The SLS AMG GT3 retained the 6.2-litre naturally aspirated V8 M159 engine from the road car, which produced 420 kW (563 hp) in standard SLS AMG trim and was one of AMG's most powerful naturally aspirated units at the time of introduction. The GT3 version adopted a sequential six-speed racing transmission with shift paddles mounted on the steering column, replacing the road car's AMG SPEEDSHIFT dual-clutch unit. An integrated multi-disc locking differential and traction control system were included.
The suspension was fully adjustable, with facilities for tuning the springs, shock absorbers, ride height, stabilisers, track width, and camber. Rack-and-pinion steering with a more direct ratio than the road car and servo assistance aided driver feedback. Braking was handled by a steel racing system with racing ABS. The driver sat in a high-strength carbon-fibre reinforced polymer safety cell with a HANS-compatible seat shell, individually foam-padded, and a six-point racing harness. An optimised fire extinguisher system and central display were positioned within the driver's field of vision.
The iconic gullwing doors of the road car were retained, and in the event of a rollover the doors could be explosively detached via pyrotechnic bolts for driver extraction — a feature shared with the production SLS AMG road car.
The SLS AMG GT3 made its competition debut at the VLN Nürburgring Endurance Championship in 2010, competing in the SP9 class with a Balance of Performance weight of 1,350 kg and an output set at 409 kW (548 hp). It won its first VLN race in October 2010.
From 2011 onwards the car competed across a broad range of GT3 series worldwide, including the FIA GT3 European Championship, the Blancpain Endurance Series, the Blancpain Sprint Series, the 24 Hours of Nürburgring, the British GT Championship, Super GT in Japan, the Australian GT Championship, the Bathurst 12 Hour, the Dubai 24 Hour, the Macau GT Cup, and the Pirelli World Challenge in North America. It was also used in the AMG Driving Academy driver training programme.
Notable results included victories at the Dubai 24 Hour in 2012 and 2013, both achieved by Black Falcon Racing. In Japanese Super GT, the car entered in the GT300 class, with Haruki Kurosawa and Hironori Takeuchi finishing joint fifth in the 2012 drivers' championship. In 2013 the car achieved prominent results: one Erebus Motorsport entry won the Liqui Moly Bathurst 12 Hour outright, and another car won the 24 Hours of Spa, recording the first Mercedes victory at that event since 1964. A special limited edition of five cars, the SLS AMG GT3 "45th ANNIVERSARY," was unveiled at the 2012 São Paulo International Motor Show to mark 45 years of the AMG brand, featuring a designo magno graphite matte finish and extensive carbon-fibre bodywork.
The SLS AMG GT3 served as Mercedes-AMG's customer racing flagship through the transition from the SLS to the AMG GT platform. It was present at the Goodwood Festival of Speed in 2011 and competed at major endurance rounds throughout its five-year campaign. The car was succeeded from 2016 by the Mercedes-AMG GT3, which used the same naturally aspirated 6.2-litre V8 engine carried over to preserve the reliability and driver-friendly characteristics that the SLS GT3 had demonstrated. The SLS AMG GT3 is considered a milestone in AMG's customer racing history, representing the brand's first wholly in-house-designed supercar adapted for top-level GT competition.