Emperor Gaozong of Tang (21 July 628 – 27 December 683), personal name Li Zhi, is the third emperor of the Tang Dynasty in China, ruling from 649 to 683 (although after January 665 much of the governance is in the hands of his second wife Empress Wu (later known as Wu Zetian)).

Emperor Gaozong is the son of Emperor Taizong and Empress Zhangsun.

Emperor Gaozong is aided in his rule by Empress Wu during the later years of his reign after a series of strokes leave him incapacitated.

Emperor Gaozong delegates all matters of state to his wife and after he dies in 683, power falls completely into the hands of Empress Wu, who subsequently becomes the only reigning Empress of China.

After his death, he is interred at the Qianling Mausoleum along with Wu Zetian.

Historians have generally viewed Emperor Gaozong as a weak ruler, inattentive to the business of the state and leaving such business to his powerful wife Empress Wu.

During the first part of his reign, Tang territorial gains, which started with his father Emperor Taizong, continued, including the conquest of Baekje, Goguryeo, and Western Tujue, but throughout the 670s, much of those gains were lost to Tufan, Silla, Khitan, and Balhae.

Further, territory previously conquered that belonged to both Eastern and Western Tujue were subjected to repeated rebellions.