The Jeju Uprising (or the Jeju Massacre) is a revolt on Jeju island off the south coast of the Korean Peninsula, beginning on April 3, 1948.

Between 14,000 and 60,000 individuals are killed in fighting between various factions on the island or are executed.

The brutal suppression of this rebellion by the South Korean army results in many deaths, the destruction of many villages on the island, and sparking rebellions on the Korean mainland.

The rebellion, which includes the mutiny of several hundred members of the South Korean 11th Constabulary Regiment, lasts until May 1949, although small isolated pockets of fighting continue into September 21, 1954.

The April 3 Uprising has become a symbol of Jeju's Independence from the Korean Peninsula.