The controversy regarding the political status of Taiwan (or "Taiwan Issue" as referred to by the Communist Party of China) hinges on whether Taiwan, Penghu, Kinmen, and Matsu should remain effectively independent as territory of the Republic of China (ROC), become unified with the territories now governed by the People's Republic of China (PRC), or formally declare independence and become the Republic of Taiwan; furthermore, on whether its existence and status as a state ("country") is legitimate and recognized by the international community.

Currently, Taiwan, Penghu, Kinmen, Matsu, and some other minor islands effectively make up the jurisdiction of the state with the official name of Republic of China but widely known as "Taiwan". The ROC, which took control of Taiwan (including Penghu and other nearby islands) in 1945, ruled mainland China and claimed sovereignty over Outer Mongolia (now Mongolia) and Tannu Uriankhai (part of which is present day Tuva, Russia) before losing the Chinese Civil War and relocating its government to Taipei, Taiwan in December 1949.

Cross-Strait relations (simplified Chinese: 海峡两岸关系; traditional Chinese: 海峽兩岸關係; pinyin: Hǎixiá Liǎng'àn guānxì) refers to the relations between mainland China and Taiwan, which are separated by the Taiwan Strait in the west Pacific Ocean, and especially the relations between their respective governments, the People's Republic of China ("PRC") and the Republic of China ("ROC").

In 1949, with the Chinese Civil War turning decisively in the Communists' (CPC) favour, the ROC government led by the Kuomintang (KMT) retreated to Taipei, in Taiwan, while the CPC proclaimed the PRC government in Beijing.

Since then, the relations between mainland China and Taiwan have been characterised by limited contact, tensions, and instability. In the early years, military conflicts continued, while diplomatically both governments competed to be the legitimate government of "China". More recently^[when?], the legal and political status of Taiwan have become more controversial, when the expression of pro-Taiwan independence sentiments are no longer suppressed and outlawed. At the same time, there has been increasing non-governmental and semi-governmental exchanges between the two sides. From 2008, negotiations began to restore the "three links" (transportation, commerce, and communications) between the two sides, cut off since 1949. Party-to-party talks between the CPC and the KMT have resumed and semi-official negotiations through organizations representing the interests of their respective governments are being scheduled.

Taiwan (ⁱ/ˌtaɪˈwɑːn/ TY-WAHN; Chinese: 臺灣 or 台灣; pinyin: Táiwān; see below), officially the Republic of China (ROC; Chinese: 中華民國; pinyin: Zhōnghuá Mínguó), is a state in East Asia. Originally based in mainland China, the Republic of China now governs the island of Taiwan (formerly known as Formosa), which forms over 99% of its current territory, as well as Penghu, Kinmen, Matsu, and other minor islands. Neighboring states include the People's Republic of China to the west, Japan to the east and northeast, and the Philippines to the south. Taipei is the capital city and economic and cultural centre of the country, and New Taipei is the most populous city.

The earliest evidence of inhabitation of Taiwan dates back to the late Paleolithic era. The island of Taiwan was mainly inhabited by Taiwanese aborigines before being colonized in the 17th century by the Dutch and the Spanish Empire. The first Han Chinese polity on Taiwan began when Koxinga's troops defeated Dutch forces and established the Kingdom of Tungning. The island was subsequently ruled by the Qing Dynasty after the kingdom's defeat in the Battle of Penghu in 1683, a period that lasted for over 200 years. Following Japan's victory over the Qing Dynasty in the first Sino-Japanese war, Taiwan was ceded to Japan under the Treaty of Shimonoseki in 1895.