The Opel Astra is a compact car/small family car (C-segment) developed and produced by the German automaker Opel since 1991, currently at its sixth generation. It was first launched in September 1991 as a direct replacement to the Opel Kadett. As of 2022, the car slots between the smaller Corsa supermini and the larger Insignia large family car.

The C-segment is the 3rd category of the European segments for passenger cars and is described as "medium cars". It is equivalent to the Euro NCAP "small family car" size class, and the compact car category in the United States.