For the 1966 MGB, the previously optional front roll bar was standardized in 1966 and all convertible tops and hardtops were black from now on. Calendar year sales were steady at 22,675 units, with 14,543 roadsters sold in the U.S.

The handsome MGB GT started to gain traction, as owners appreciated that the occasional rear seat could accommodate two children and the handsome Pininfarina-designed hatchback rear. MGB GT sales climbed to 10,241 units, with 5861 headed for the U.S. and 2,415 staying in the UK.

Early MGBs had one of two convertible tops. The most common was the so-called pack-away top which could be dismantled and put in the trunk, enabling enough room for a child behind the front seats. Early cars had and optional cushion for the rear deck. Some cars had an attached folding convertible top which was finally standardized in the Mk II model in 1970. A top boot was included and matching tonneau cover was optional. Black, Red, Gray, Blue or White fiberglass factory hardtops were optional. All convertible tops were black from 1967 on.