Wang Mang (Chinese: ) (c. 45 BC 6 October 23 AD), courtesy name Jujun (Chinese: ; pinyin: Jjn), was the founder and the only emperor of the short-lived Chinese Xin dynasty. He was originally an official and consort kin of the Han dynasty and later seized the throne in AD 9. The Han dynasty was restored after his overthrow, and his rule marked the separation between the Western Han dynasty (before Xin) and Eastern Han dynasty (after Xin). Traditional Chinese historiography viewed Wang as a tyrant and usurper, while more recently, some historians have portrayed him as a visionary and selfless social reformer. During his reign, he abolished slavery and initiated a land redistribution program. Though a learned Confucian scholar who sought to implement the harmonious society he saw in the classics, his efforts ended in chaos.

Wang Mang's late reign saw large-scale peasant rebellions, most notably the revolt of the Red Eyebrows. In October 23 AD, the capital Chang'an was attacked and the imperial palace ransacked. Wang Mang died in the battle. The Han dynasty was re-established in either 23 AD when the Gengshi Emperor took the throne, or in 25 AD when Emperor Guangwu of Han took the throne after defeating the Red Eyebrows who deposed the Gengshi Emperor.

The Xin dynasty (; Chinese: 新朝; pinyin: Xīncháo; Wade–Giles: Hsin¹-chʻao²; lit. 'New dynasty') was a short-lived Chinese dynasty which lasted from 9 to 23 AD, established by the Han dynasty consort kin Wang Mang, who usurped the throne of Emperor Ping of Han and the infant "crown prince" Ruzi Ying to rule the empire over a decade before being overthrown by rebels. After Wang's death, the Han dynasty was restored by Liu Xiu, a distant descendant of the Emperor Jing of Han; therefore, the Xin dynasty is often considered an interregnum period of the Han dynasty, dividing it into the Western Han (or "Former Han") and the Eastern Han (or "Later Han").