Emperor Zhongzong of Tang (26 November 656 – 3 July 710), personal name Li Xian, and at other times Li Zhe or Wu Xian, was the fourth and seventh emperor of the Tang dynasty of China, ruling briefly in 684 and again from 705 to 710. During the first period, he did not have actual power, which was in the hands of his mother, Empress Wu Zetian and he was overthrown on her orders after opposing his mother. During his second reign, most of the power was in the hands of his consort Empress Wei.

Emperor Zhongzong was the son of Emperor Gaozong of Tang and Empress Wu (later known as Wu Zetian), and during the reign of his father, Emperor Zhongzong's mother Empress Wu, not Emperor Gaozong, was in actual control of power as empress consort and power behind the emperor. He succeeded his father in 684, But as emperor, he had no true power, and all authority remained in the firm hands of his mother, Empress Dowager Wu. His mother, however, deposed him less than two months later in favor of his younger brother Emperor Ruizong. The former emperor, demoted to a princely rank, was exiled to the provinces and placed under house arrest. Six years later, Emperor Ruizong relinquished the throne to his mother and Empress Dowager Wu officially proclaimed herself empress regnant, while Emperor Ruizong was made crown prince.

By 698, the court was caught in the middle of a bitter power struggle. In an attempt to secure her prominence, Empress Wu liberated the former emperor from his 14 years of seclusion and recalled him to the capital in April 698. He was reinstated as crown prince in October 698, taking his brother's place. On 20 February 705, a palace coup (Shenlong Coup) deposed Wu Zetian and Emperor Zhongzong was restored as emperor three days later. Emperor Zhongzong reigned for five years but was a totally weak, carefree, cowardly, shy, henpecked weakling and easily influenced ruler. Thus, real power was in the hands of his empress consort, Empress Wei and her lover Wu Sansi (Wu Zetian's nephew) and his daughter Li Guo'er, the Princess Anle. He was relatively similar to his father. Of course, Emperor Gaozong was able to make decisions, although he did it slowly in government affairs, but various debilitating diseases until his death became the main reason for handing over power to his wife Empress Wu. In contrast, Emperor Zhongzong likely had depression due to his long duration under house arrest; this encouraged him to hand over power to his wife and daughter.

In 710, Emperor Zhongzong died, allegedly poisoned by Empress Wei, who then installed his son, Li Chongmao, as Emperor Shang. Empress Wei, who had failed to install her daughter Li Guo'er, the Princess Anle, as heir to Emperor Zhongzong, thought that Li Chongmao, born of Zhongzong and a concubine and who was only 16 years old, would be easy to control and allow her to preserve her power. The scheme failed, however, when Princess Taiping, the sister of Emperor Zhongzong, launched a coup two weeks later with her nephew Li Longji (later Emperor Xuanzong), son of the abdicated Emperor Ruizong, and overthrew Empress Wei and the young emperor. Emperor Ruizong, the father of Li Longji and the older brother of Princess Taiping, was restored as emperor.