The Triumph TR3 is a sports car produced between 1955 and 1962 by Standard-Triumph in England. The facelifted variant, popularly but unofficially known as the TR3A, entered production in 1957 and the final version, unofficially the TR3B, was produced in 1962.

The car was powered by a 1991 cc straight-4 OHV engine initially producing 95 bhp (71 kW; 96 PS), an increase of 5 hp over the TR2 thanks to the larger SU-H6 carburettors fitted. The four-speed manual gearbox could be supplemented by an overdrive unit on the top three ratios, electrically operated and controlled by a switch on the dashboard. In 1956 the front brakes were changed from drums to discs, the TR3 thus becoming the first British series production car to be so fitted.

The TR3 is a true roadster, designed for sunny weather but with removable rain protection. It has a convertible hood (US top) that snaps on and off and removable side curtains, allowing very low doors with padding for the driver's arm to rest on. There are holes in the floor, with rubber plugs, so that the originally supplied jack might be used from inside the car, as did the Jaguar XK120. The optional heater was poor and the shut-off valve was under the bonnet (US hood).

In June 1977, the American Road & Track magazine published an article titled "Driving Impressions: TR3A & TR250" in its 30th anniversary issue. It published a 0–60 mph time of 12.0 seconds, power output of 100 bhp (75 kW) at 4800 rpm, and fuel consumption of 10 liters / 100 km.