During World War II, Madagascar was aligned with Vichy France until 1942, when it was conquered by the British; in 1943 the Free French regime assumed control. From 1947 to 1948 there was a major uprising against the French, who crushed the rebellion, killing between 11,000 and 80,000 (estimates vary) Malagasy in the process. As in other French colonies, indigenous political activity increased in 1956, and the Social Democratic party (PSD), led by Philibert Tsiranana (a Tsimihety), gained predominance in Madagascar.

On Oct. 14, 1958, the country—renamed the Malagasy Republic—became autonomous within the French Community and Tsiranana was elected president. On June 26, 1960, it became fully independent. Under Tsiranana (reelected in 1965 and 1972), an autocratic ruler whose PSD controlled parliament, government was centralized, the coastal peoples (côtiers) were favored over those of the interior (especially the Merina), and French economic and cultural influence remained strong. Beginning in 1967, Tsiranana cultivated economic relations with white-ruled South Africa