German automotive company, a wholly owned subsidiary of the U.S. General Motors Corporation, specializing in the manufacture of passenger cars, minibuses, and light vans. Headquarters are in Rüsselsheim, Ger.

The company was started in 1898 when the five Opel brothers began converting the bicycle and sewing machine factory of Adam Opel (1837–95) into the automobile complex that before World War II was to produce more cars than any other European facility. In their first year of production, they brought out the Opel-Lutzmann but soon abandoned it. The firm introduced its first original model, a twin-cylinder Opel, in 1902.

The company was emerging as a major force in the early development of the auto industry when in 1911 the plant was destroyed by fire. Forced to rebuild from scratch, Opel took advantage of the opportunity to retool with the most modern and efficient equipment. In 1913 Opel trucks were added to the product line. Although production was restricted following Germany's defeat in World War I, productivity improved as Opel became the first German manufacturer to adopt the efficient assembly-line method of operation. One of its most distinctive roadsters of this period was the Laubfrosch, or tree frog, so named for its green colour.

The hyperinflation and economic uncertainty of the 1920s prompted the Opel family to relinquish control of the firm, ultimately to General Motors. With the defeat of Germany in World War II, Opel lost a portion of its facilities to the Soviet Union but quickly resumed production of its remaining lines. As one of the largest industrial firms in Europe, Opel accounts for about one-quarter of all German vehicle output and exports mainly to other European countries and South Africa.