French Indochina (previously spelled as French Indo-China), officially known as the Indochinese Union and after 1947 as the Indochinese Federation, was a grouping of French colonial territories in Southeast Asia until its demise in 1954. It comprised Cambodia, Laos (from 1899), the Chinese territory of Guangzhouwan (from 1898 until 1945), and the Vietnamese regions of Tonkin in the north, Annam in the center, and Cochinchina in the south. The capital for most of its history (1902–1945) was Hanoi; Saigon was the capital from 1887 to 1902 and 1945 to 1954.

The Second French Empire annexed Cochinchina and established a protectorate in Cambodia in 1862 and 1863, respectively. After the French Third Republic took over northern Vietnam through the Tonkin campaign, the various protectorates were consolidated into one union in 1887. Two more entities were incorporated into the union: the Laotian protectorate and the Chinese territory of Guangzhouwan. The French exploited the resources in the region during their rule but also contributed to improvements in the health and education system in the region. Nevertheless, deep divides remained between the native population and the colonists, leading to sporadic rebellions by the former.