Emperor Wenzong of Tang (809840), personal name Li Ang, n Li Han (), was an emperor of the Tang dynasty of China. He reigned from 827 to 840. Emperor Wenzong was the second son of Emperor Muzong and younger brother of Emperor Jingzong. A rare occurrence in Chinese history, Emperor Wenzong, along with his elder brother Emperor Jingzong and younger brother Emperor Wuzong, reigned in succession.

The Sweet Dew incident (Chinese: 甘露事變) was an incident on December 14, 835, in which Emperor Wenzong of the Chinese Tang dynasty, angry about the power of his eunuchs, conspired with the chancellor Li Xun and the general Zheng Zhu to slaughter the eunuchs. The plot failed, however, when the eunuchs realized what was happening and counterattacked with soldiers under their command. Li Xun, Zheng, as well as many of their associates and other officials were slaughtered, and thereafter, the eunuchs had an even firmer control over Emperor Wenzong and his government than before.