The national Flag of the Republic of China (traditional Chinese: 中華民國國旗; simplified Chinese: 中华民国国旗; pinyin: Zhōnghuá Mínguó guóqí) is a well-known symbol of the Republic of China (ROC). It is commonly referred to in Chinese as Blue Sky, White Sun, and a Wholly Red Earth (traditional Chinese: 青天、白日、滿地紅; simplified Chinese: 青天、白日、满地红; pinyin: qīng tiān, bái rì, mǎn dì hóng) to reflect its attributes. This design was first used in China by the Kuomintang (KMT) in 1917 and made the official flag of the ROC in 1928.

The current use of the flag is considered by some to be controversial due to the dispute over the political status of Taiwan. Within Taiwan, the flag is widely used as a national flag though there is controversy over its appropriateness. It is actively embraced as a symbol by Chinese reunification supporters as a historical link with mainland China, while a number of Taiwan independence supporters shun the flag for mainly the same reasons. Its use has been opposed by the People's Republic of China (PRC) because it suggests the continued existence of the ROC, which the PRC regards as defunct and to have been succeeded by the PRC in the Chinese Civil War. However, since the early 2000s, the PRC has had a more favorable view toward the flag, as it began to see the use of the flag in Taiwan as symbolizing a connection between Taiwan and mainland China, and news media in the PRC have often criticized supporters of Taiwanese independence for attempting to replace the flag.