Opel, originally and more correctly known as Adam Opel AG is an automobile maker in Germany. It opened for business on January 21, 1863 and at first made household goods. The founder died in 1895, with his company the leader in European sewing machines sales and producing over 2,000 bicycles yearly. Then by 1899 as the Opel company started to build cars. However, two years later, following the dissolution of his partnership, Opel signed a licensing agreement with Automobiles Darracq S.A. of France to manufacture vehicles under the brand name "Opel-Darracq." The vehicles were Opel bodies mounted on a Darracq chassis, powered by a 2-cylinder engine.

Since 1929, Opel has been part of General Motors. Many cars sold by General Motors worldwide are Opel designs, including such models as the Corsa, Astra, Vectra and Omega. Opel models are also sold under other GM brand names, such as Vauxhall in the UK, Holden in Australasia, and Chevrolet in Latin America. Its Zafira people carrier was sold in Japan badged as a Subaru Traviq, while the Omega was briefly sold in the US as the Cadillac Catera. Other models sold in the US, but slightly modified, include the Saturn L-series, Chevrolet Malibu and Cobalt, and the upcoming Saturn Aura. The first cars produced by Daewoo in South Korea for export to North America were based on the Opel Kadett (now Astra) and larger Rekord (now Omega). Opels appeared under their own name in the US in the late Sixties, when they were sold through Buick dealers as captive imports.

Opel is the main GM brand name in Europe except in the UK, where GM's other European subsidiary, Vauxhall Motors, still uses its own brand name. Vauxhall's models were completely different designs from those of Opel, until the 1970s. The Opel name largely disappeared from the UK in 1981 after Vauxhall and Opel dealerships were merged, with only the Manta and the Monza (the coupe version of the Senator) being sold as Opels, until they were discontinued in 1988 and 1987 respectively.

Vauxhall began adopting Opel's names for its models, with the exception of 'Kadett' which was replaced by Astra, already used by Vauxhall, in 1991. In other right hand drive markets in Europe like Ireland, Cyprus and Malta, the main GM brand name is now Opel, and for many years, Opel Ireland sponsored the Republic's soccer team, using the slogan 'Ireland's Number One Supporter'. However, many Vauxhall cars, imported second hand from the UK, are still sold in Ireland.

Some have suggested that the Vauxhall name should be dropped in the UK in favour of Opel, thereby harmonising GM's marketing strategy across Europe. However, Vauxhall has rejected this, on the grounds that its brand is well known, and fleet buyers, who are its main customer base, insisted that Opel models be rebadged as Vauxhalls. Another chance is taking place to actually kill off the name starting with V and replace it with something like Opel UK (will also abbreviate a new chance to also give it another name too, Opel Great Britain).

The company headquarters are located in Rüsselsheim, and it has plants in Bochum and Eisenach and Kaiserslautern as well as in Belgium, Spain and Poland. Opel cars are also made in Vauxhall's Ellesmere Port plant in the United Kingdom.

In October 2004 employees went on strike for six days due to the threat of 12,000 job losses. The threat was due to the unprofitable European markets because of low customer demand. The strike had a major impact on production. Employee negotiations are still underway to come to an acceptable deal.

In December 2004 General Motors rumored to sell its Opel / Vauxhall business to Volkswagen.