The MGA's bodywork was based largely on that of a one-off MG TD specially built by the MG factory at the request of racing privateer George Phillips for the 1951 24 Hours of Le Mans. Later, a new chassis was designed so as to seat the driver lower in the car with even cleaner bodywork resulting in the EX 175 prototype. The later MG prototype EX 182 was very close to the final production MGA and was the car actually raced at Le Mans in 1955. Three MGA prototypes were entered at Le Mans in 1955. Two of the cars finished the race placing 12th and 17th overall, proving the worth of the new car. The third car crashed with serious injuries to the driver, Dick Jacobs.

The car was in production from 1955 until 1962 when it was replaced by the MGB. Throughout its production life it received a number of upgrades, increasing engine displacement and power and improvements to brakes, suspension and trim. It used the BMC B series engine initially at 1500cc, later a 1600 twin cam engine was made available and finally 1622cc on the MkII car. It was a great export success, of just over 100,000 cars produced 95% were sold outside the UK.