The Chinese Civil War was a civil war in China fought between the Kuomintang (KMT)-led government of the Republic of China (ROC) and forces of the Chinese Communist Party (CCP) lasting intermittently after 1927.

The war is generally divided into two phases with an interlude: from August 1927 to 1937, the KMT-CCP Alliance collapsed during the Northern Expedition, and the Nationalists controlled most of China. From 1937 to 1945, hostilities were put on hold, and the Second United Front fought the Japanese invasion of China with eventual help from the Allies of World War II. The civil war resumed with the Japanese defeat, and the CCP gained the upper hand in the final phase of the war from 1945 to 1949, generally referred to as the Chinese Communist Revolution.

The Communists gained control of mainland China and established the People's Republic of China (PRC) in 1949, forcing the leadership of the Republic of China to retreat to the island of Taiwan. Starting in the 1950s, a lasting political and military standoff between the two sides of the Taiwan Strait has ensued, with the ROC in Taiwan and the PRC in mainland China both officially claiming to be the legitimate government of all China. After the Second Taiwan Strait Crisis, both tacitly ceased fire in 1979, however, no armistice or peace treaty has ever been signed.