Cochin China (also known as Cochinchina or in French, Cochinchine) was the southernmost part of Vietnam beside Cambodia.

Originally called Jiaozhi (交阯 or 交趾) by its Chinese rulers, Cochin was named after the unknown realm south of the Five Mountain Ranges (五嶺) in the legendary time of Sanhuangwudi. Its name may be phonetic, but the characters also have the meaning of "crossed bases of hills" and "crossed toes." Locally, it is called Nam Bộ, meaning "Southern Boundary."

In 111 BC, under the reign of Wudi of Han China, the Jiaozhi Commandry (交趾郡) was established, among two other commandries in other parts of Vietnam: Jiuzhen (九真郡) and Ri'nan (日南郡). In 939, Ngô Quyền (吳權) proclaimed himself King of the Cochin Kingdom and started the Ngo Dynasty.

During the French occupation, it was called Cochinchine in French, and its capital was at Saigon. The two other parts of Vietnam at the time were Annam and Tonkin.

Cochin China is also a type of domestic fowl.