The Mark 2 Astra was launched on 17 October 1984. It used the same range of engines and running gear as the Mark 1, but with a completely restyled body with better aerodynamics, being a rebadged version of the Opel Kadett E. It was voted 1985 European Car of the Year. Long-lived, remaining in production until 1991, the Mark 2 Astra was available in estate, hatchback, saloon and cabriolet versions. Bertone built 6,764 cabriolets from 1987 to 1993. These came as 1.6 with 82 bhp and 2-litre 115 bhp GTEs, the latter available with powered roof and electric windows. These cars are praised for their shake-free shells and their looks.

The Mark 2 Astra sold well in the UK, and although it was never able to outsell the Ford Escort, it came closer than any other similar-sized car to achieving this.

Soon after the Mark 2 Astra was launched, Vauxhall introduced the GTE using a 1.8-litre 115 hp engine lifted from the Mark 1 GTE, but this was quickly dropped in favour of a 124 hp 2.0 litre unit due to poorer than expected performance. GTE models featured an all electronic dash with digital speedometer. Analogue instruments were an optional extra, but were very rarely selected. In 1988 Vauxhall's twin-camshaft version of the engine, the C20XE known as the "red top" (due to the red spark plug cover), was fitted to the GTE and instantly created a stir with the motoring press because of its performance.