The Opel Omega is an executive car engineered and manufactured by German automaker Opel between 1986 and 2004. The first generation, the Omega A (1986–1993), superseded the Opel Rekord. It was voted European Car of the Year for 1987, and was available as a saloon or estate. The second generation, the Omega B, was manufactured from 1993 to 2004.

Rebadged variants of the Omega were marketed worldwide, including in North America as the Cadillac Catera, in Great Britain as the Vauxhall Omega, and South America as the Chevrolet Omega. As with the Rekord which preceded it, re-engineered versions of the Omega were manufactured in Australia from 1988 as the Holden Commodore (and its derivatives) since 1999. Commodore-based cars were in turn exported to South America as the Chevrolet Omega and to the Middle East as the Chevrolet Lumina.

Production of the Omega was discontinued in 2004. It was succeeded by the Opel Signum.