Mercedes-AMG presented the original GT3 race car at the Geneva Motor Show in March 2015, derived from the then-new AMG GT road car introduced the previous year. Rather than using the road car's 4.0-liter twin-turbocharged V8, the GT3 retained the naturally aspirated M159 6.2-liter V8 engine previously used in the SLS AMG GT3, with engineers citing the older engine's user friendliness and proven reliability as key factors. The car's body is constructed largely from carbon-fiber-reinforced polymer to bring the vehicle's weight below 1,300 kg in compliance with FIA GT3 regulations.
The first-generation car entered competition in 2016. Customer teams AKKA ASP, Black Falcon, HTP Motorsport, and Zakspeed competed in the Blancpain Endurance Series that season. Zakspeed also ran in the ADAC GT Masters. At the 2016 24 Hours Nürburgring, the AMG GT3 achieved a dominant 1-2-3-4 and 6th place result. New Zealand driver Craig Baird gave the car its first race win anywhere at round two of the 2016 Australian GT Championship, held at the Melbourne Grand Prix Circuit as a Formula 1 support race.
An updated version, the AMG GT3 Evo, was introduced at the 24 Hours of Nürburgring in June 2019 for the 2020 racing season. Updates included an automatic data logger and analysis system, the ability to automatically start the engine when lowered from its air jacks, and new brake and traction control systems. Aerodynamic changes included a revised front splitter and rear wing designed for faster trackside adjustment, and design updates aligned the car's styling with the updated AMG GT road car, particularly new headlamps and a revised grille that provided improved radiator protection. The car continued to use the same 6.2-liter V8 as the original GT3.
In the 2017 IMSA SportsCar Championship, Riley Technologies entered two customer AMG GT3s in the GTD class, with one of the cars winning the GTD class at the 12 Hours of Sebring. By June 2019, a total of 130 GT3 cars had been sold globally.
In the 2016 Super GT GT300 class, the AMG GT3 made its debut with multiple Japanese customer teams including Good Smile Racing with Team UKYO, GAINER, LEON Racing, and Rn-sports, replacing the older SLS AMG GT3s that had previously been used by those teams.
The road-going AMG GT variants served as the official Formula 1 safety car for multiple seasons. The GT S held this role in 2015, 2016, and 2017 before being replaced by the GT R from 2018 to 2021. From 2022, the GT R was replaced by the GT Black Series. The racing GT3's aerodynamic styling influenced subsequent road-car variants, with the distinctive Panamericana grille from the GT3 and GT4 becoming standard equipment across the AMG GT road car family following a 2017 facelift.
In January 2025, Mercedes-AMG confirmed development of a second-generation AMG GT3 based on the C192 platform, the second-generation AMG GT road car. The company stated that track testing would begin later in 2025, with a customer racing debut expected in 2027. The new car was revealed on March 23, 2026. It will be the first Mercedes race car developed by Affalterbach Racing GmbH, a new wholly-owned subsidiary of Mercedes-AMG created specifically for motorsport activities.
A GT4 version of the Mercedes-AMG GT was presented at the 2017 24 Hours of Spa. Based on the GT R road variant, the GT4 is aimed at semi-professional drivers and debuted at the ROWE 6 Stunden ADAC Ruhr-Pokal-Rennen. The car received significant upgrades for the 2022 season and has established a strong presence in GT4-class championships globally.
In iRacing, the Mercedes-AMG GT3 is part of the platform's GT3 class roster, competing alongside other GT3 cars in multiclass and dedicated GT3 series. The car reflects the AMG GT3 Evo specification and is used across the wide variety of road courses available on the service. iRacing's GT3 content draws from real-world GT3 homologation specs, and the Mercedes entry is among the options available to drivers competing in the platform's GT endurance events.