The McLaren MP4-12C — later rebranded simply as the McLaren 12C — was produced between 2011 and 2014 at McLaren's facility in Woking, Surrey. The car marked McLaren's return to production car sales for the first time since the F1 ceased production in 1998, with development beginning in 2005 and the car making its online debut in September 2009. It features a carbon fibre structure called the MonoCell, manufactured by Carbo Tech in Salzburg, Austria, weighing 80 kilograms. The 12C is powered by a 3.8-litre twin-turbocharged V8 engine codenamed M838T, produced by Ricardo PLC in West Sussex, generating 453 kilowatts (616 PS) and a torque output of 601 Nm. It uses a seven-speed dual-clutch gearbox manufactured by Graziano and a double wishbone hydraulic suspension system. More than 3,400 units were produced before the car was succeeded by the 650S in 2014.
In December 2010, McLaren announced plans to produce a small number of MP4-12C cars for FIA Group GT3 competition, committing to providing factory maintenance support. The car received its competitive debut with a single entry at the Spa Francorchamps round of the British GT Championship, followed by a three-car entry in the 2011 Spa 24 Hours. A further car was entered in the GT Cup class at the 2011 Macau Grand Prix, driven by Danny Watts.
Compared to the road car, the MP4-12C GT3 produces reduced power — approximately 493 bhp (500 PS) — due to GT3 homologation requirements. A bespoke six-speed sequential gearbox, developed with Ricardo, replaces the road car's seven-speed dual-clutch unit and saves 80 kg. The steering wheel is sourced from the McLaren MP4-24 Formula 1 car.
In March 2012, McLaren readied 25 MP4-12C GT3 cars for a full racing season. The 2012 FIA GT1 World Championship saw McLaren GT partner team Hexis Racing campaign the car, and the 12C GT3 took its first international victories at the two races of the Circuito de Navarra round of the 2012 FIA GT1 World Championship season. Formula 1 driver Lewis Hamilton drove the car in promotional material in the lead-up to the 2012 racing season.
The MP4-12C HS road variant, released in March 2012 and limited to 10 units, drew directly on the GT3 car's aerodynamic development: it incorporated a revised front end, rear bumper, larger vents and diffuser, and a modified rear wing inspired by the GT3 race car's bodywork, alongside a 75 horsepower power increase.
The 12C GT3 established McLaren Automotive's credibility as a customer racing program and laid the groundwork for the longer-running 650S GT3 and 720S GT3 programs that followed. The car's MonoCell carbon chassis carried from the road car gave it a structural advantage over conventional steel-framed competitors. McLaren GT, the racing division supporting the customer program, developed into one of the more active factory-backed GT3 operations in Europe through the mid-2010s, with the 12C GT3's competitive debut at Spa and in the FIA GT1 World Championship representing the first step in that trajectory.