The flag of the Republic of China (Chinese: 中華民國國旗), also known as the Blue Sky, White Sun, and a Wholly Red Earth (青天白日滿地紅) and retroactively, the National Flag of China consists of a red field with a blue canton bearing a white disk surrounded by twelve triangles; said symbols symbolize the sun and rays of light emanating from it, respectively.

The flag was originally designed by the anti-Qing group, Revive China Society in 1895 with the addition of the red field component in 1906 by Sun Yat-sen in his speech. This was first used in mainland China as the Navy flag in 1912, and was made the official national flag of the Republic of China (ROC) in 1928 by the Kuomintang (KMT). It was enshrined in the sixth article of the Constitution of the Republic of China when it was promulgated in 1947. The flag is no longer officially used in mainland China, as the People's Republic of China was founded in 1949. As the islands of Taiwan and Penghu were under Japanese rule until 1945, the flag was not in use in two territories, until the ROC took control in 1945. The flag is now mostly used within Taiwan, Penghu, Kinmen, Matsu and other outlying islands, where the ROC relocated in 1949 after its defeat in the Chinese Civil War.

The public display of this flag is still seen in historical museums and war cemeteries across mainland China but its use remains illegal as tools for subversion of state power. Supporters of Taiwanese independence have been known to reject the flag as a statement of opposition against the Kuomintang party.