French Cochinchina, sometimes spelled Cochin-China (French: Cochinchine Française, Vietnamese: Nam Kỳ), is a colony of French Indochina, encompassing the Cochinchina region of southern Vietnam.

Formally called Cochinchina, it is renamed in 1946 as Autonomous Republic of Cochinchina, a controversial decision that helps trigger the First Indochina War.

In 1948, the autonomous republic, whose legal status had never been formalized, is renamed as the Provisional Government of South Vietnam (not to be confused with the 1969–76 Viet Cong government).

It is reunited with the rest of Vietnam in 1949.

In Vietnamese, Cochinchina is called Nam Kỳ (Southern country) although those advocating independence prefer to use the term Nam Bộ (Southern region).

Historically, it was Gia Định (1779–1832), Nam Kỳ (1834–1945), Nam Bộ (1945–48), Nam phần (1948–56), Nam Việt (1956–75), and later Miền Nam.

In French, it is called la colonie de Cochinchine.

Vietnam was divided in the seventeenth century between the Trịnh Lords to the north and the Nguyễn Lords to the south.

The northern section is called Tonkin by Europeans, and the southern part called Cochinchina by most Europeans and Quinam by the Dutch

During the French colonial period, the label moves further south, and comes to refer to the southernmost part of Vietnam, controlled by Cambodia in prior centuries, and lying to its southeast.

Its capital is at Saigon.

The two other parts of Vietnam at the time are known as Annam and Tonkin.

The name "Cochinchina" was coined by Portuguese traders circa 1516, who named it "Cochin-China" to distinguish it from the city and princely state of Cochin in India, their first headquarters in the Malabar Coast, from the Malay Kuchi which referred to all of Vietnam, a term derived from the Chinese Jiāozhǐ, pronounced Giao Chỉ in Vietnam.