Emperor Ai of Han, personal name Liu Xin, was an emperor of China's Han dynasty. He ascended the throne when he was 20, having been made heir by his childless uncle Emperor Cheng, and he reigned from 7 to 1 BC.

Throughout Chinese history, "Emperor" was the superlative title held by the monarchs who ruled various imperial dynasties. In traditional Chinese political theory, the emperor was the "Son of Heaven", an autocrat with the divine mandate right to rule all under Heaven. Emperors were worshiped posthumously under an imperial cult. The lineage of emperors descended from a paternal family line constituted a dynasty, and succession in most cases theoretically followed agnatic primogeniture.