The TX Gemini was built at Holden's factory at Acacia Ridge, Queensland, and contained a high percentage of Australian content.

A new Smiths-brand heater, defogger, and ventilation system was used, and the two small vents at each end of the dash were removed on this model, except on vehicles fitted with air conditioning.

[4] A "Fashion Pack" interior was now available on both sedan and coupe models; this option was also upgraded to add steel-belted radials and a front stabilising bar.

They were identified by a black grille with stainless steel top edge, gold pin stripes, chequered cloth seat inserts and door trims, wood-grain dash sections, radio/cassette player, a four-spoke steering wheel, and the A9R (Fashion Pack) suspension package.

[6] The TD series was introduced in April 1978, with the most major change over the TC being the introduction of "radial tuned suspension" and the option of a five-speed manual transmission.

[7] The differential was replaced with a small Salisbury unit as used in the UC Torana; it used tapered Timken wheel bearings as found on all larger Holdens since mid-1971.

Coupes and sedans had colour-coded side mirrors similar to those of Sunbird SL/E and HZ Sandman, door-trims were extended to cover the top of the doors.

It featured significant exterior changes with new front and rear styling, comparable with the Isuzu Gemini and Holden Commodore models of the same era.

Initially only available as a sedan, in February 1980, the panel van and station wagon were added to the line-up, while the coupé version was no longer available.

The Gypsy featured blacked-out grille treatment and door window surrounds, square headlights, full chrome bumpers, and full-length headlining and carpet (regular vans had vinyl flooring as standard).

The SL and SL/X versions of TG had an appearance exactly like the TF SL/X, with the flush head lamps, plastic bumpers, and tail lights very similar to that on a VH Commodore.

The ZZ/Z was always silver, with a body kit consisting of a front bar, wind splitters on top of the guards, a bobtail boot spoiler, alloy wheels, and blue and black ZZ/Z decals.

The ZZ/Z was often thought to come with the twin-cam engine that was used in the Isuzu Gemini ZZ/R of the same era, but the ZZ/Z was strictly a cosmetic version and came with the standard running gear of other models.

Sourcing the parts from General Motors' Brazilian operation was considered, but was too complicated for the short time the model had left.

The RB Gemini was offered only in four-door sedan form, with SL/X and SL/E trim levels, as well as a fleet-only SL equipped with a 1.6 litre engine.

The RB Gemini was notable for its 80-day, 200,000 km (120,000 mi) endurance run from a commercial in 1985, tested by a group of Australian racers including the late Peter Brock.

In Australia, the 1982–1984 Holden Gemini was assessed in the "Used Car Safety Ratings" 2006 as providing "significantly worse than average" protection for its occupants in the event of a crash.