The fixed-roof MGB GT was introduced in October 1965. Production continued until 1980, although export to the US ceased in 1974. The MGB GT sported a ground-breaking greenhouse designed by Pininfarina and launched the sporty "hatchback" style. By combining the sloping rear window with the rear deck lid, the B GT offered the utility of a station wagon while retaining the style and shape of a coupe. This new configuration was a 2+2 design with a right-angled rear bench seat and far more luggage space than in the roadster. Relatively few components differed, although the MGB GT did receive different suspension springs and anti-roll bars and a different windscreen which was more easily and inexpensively serviceable.

Although acceleration of the GT was slightly slower than that of the roadster, owing to its increased weight, top speed improved by 5 mph (8.0 km/h) to 105 mph (169 km/h) because of better aerodynamics.