The Opel 1,2 Liter is a small car manufactured by Opel between 1931 and 1935. The 1,2 Liter was replaced in 1935 by the Opel P4 which was broadly similar but employed a new engine and continued in production until December 1937. For just one year, in 1933, the manufacturer also offered the Opel 1,0 Liter which was a smaller engined version of the 1,2 Liter. The Opel 1,2 Liter replaced the last version of the Opel Laubfrosch and was itself first complemented and then effectively replaced by the more roomy Opel Kadett, which had itself already entered production in 1935.

Opel Automobile GmbH, usually shortened to Opel, is a German automobile manufacturer which has been a subsidiary of Stellantis since 16 January 2021. It was owned by the American automaker General Motors from 1929 until 2017 and the PSA Group prior to its merger with Fiat Chrysler Automobiles to form Stellantis in 2021. Most of the Opel lineup is marketed under the Vauxhall Motors brand in the United Kingdom since the 1980s. Some Opel vehicles were badge-engineered in Australia under the Holden brand until 2020, in North America and China under the Buick, Saturn, and Cadillac brands, and in South America under the Chevrolet brand.