Ginetta was founded by the Walklett brothers Douglas, Trevor, Ivor and Bob, who built their first sports car based on a Wolseley Hornet. Encouraged by friends who wanted their own replicas, Ginetta went into production in 1958 with the Ford engined G2. Typical of low production British sports cars of the time, it consisted of an open fiberglass body mounted on a steel spaceframe chassis. Ginetta's big break came with the little G4, unveiled in 1962. This was designed around the new Ford family of oversquare engines, in 73.2-,81.8- and 91.5-cu in (1.2, 1.3 and 1.5 liter) forms. It was designed as much for racing as the road, and was particularly successful on track, the modest power compensated by fine road-holding and low weight. But the Walkletts had ambitions to conquer the U.S. market, and launched the more luxurious 286.8-cu in (4.7-liter) Ford V8-engined G10 in 1965. This was indeed luxurious compared to the G4: it even had wind-up windows.
The G10 also made a promising competition debut, but component supply problems meant only six cars were finished before the type was dropped. It was followed by the similar-looking G11, this time with MGB 109.8-cu in (1.8-liter) powertrain: again parts supply held it up, and only 12 G11s were made. The G12 of 1966 was very different, claimed to be the first British mid-engined car and designed exclusively for racing, though some were used on the road. Meanwhile, the Walklett brothers were looking around for a successor to the G4. When it arrived in 1967, however, the G15 was quite different. It was a pure road car, a closed two-seater powered by the smooth, tuneable 53.4-cu in (875-cc) Hillman Imp engine. This turned out to be Ginetta's most successful car so far: it was cheap to insure, could top 100mph (160 km/h) and achieved 50 mpg (17.7km/liter). The G15's success prompted Ginetta to abandon the attractive mid-engined G20 and delayed the more conventional G21, a pretty 2+2 coupe powered by a 77.8-cu in (J.7-Jitre) Hillman engine until 1973.
Ten years later, the G25 was unveiled as the spiritual successor to the G15, this time mid-engined, with Ford Fiesta components. But it was abandoned when Toyota's MR2 appeared, underlining the fact that a Ginetta would need to offer at least the same level of performance. Instead, the G32 was developed, mid-engined again, but with the 105-bhp (78.3-kW) 97.6-cu in (1.6-liter) engine from the Ford XR3. By 2002 Ginetta was offering a range of three cars, though it had gone back to its front-engined origins. The G20 was described as a modern G4, with a choice of Ford Pinto or Zetec engines and a glassfibre body and steel spaceframe, while the G27 was an updated G4 with the same engine options. Finally, the G33 was launched in 1990 as an upmarket car, slightly longer and wider than the G20/27 with Ford Zetec 2-liter or Rover V8 engines available. Mark Walklett (son of Trevor) was involved in the design.