The Gang of Four was a Maoist political faction composed of four CCP officials. They came to prominence during the Cultural Revolution (1966-1976) and were later charged with a series of treasonous crimes. The gang's leading figure was Jiang Qing (Mao Zedong's fourth and last wife). The other members were Zhang Chunqiao (a Chinese labour activist), Yao Wenyuan (a Chinese literary critic and politician), and Wang Hongwen (a well-known Chinese political theorist).

All four members were devoted to Mao because he had elevated them from lower positions. Before the start of the Cultural Revolution, each member of the Gang of Four held low or middle ranks within the government.

Together with general Lin Biao, the Gang of Four, were labelled the two major "counter-revolutionary forces" of the Cultural Revolution and officially blamed by the Chinese government for the worst excesses of the societal chaos that ensued during the ten years of turmoil. It is said that while Lin was attempting to flee from Mao, as well as from the fallout of his alleged coup, he was killed in a plane crash in 1971, along with several members of his family. He was immediately vilified by the Gang of Four, whom he had brought together in the first place. By 1974, they had begun an intense campaign to smear his memory. The Gang of Four again drew Mao's attention when they began to try to undermine Zhou Enlai. They tried to criticize him and the bureaucrats Zhou had helped to restore to their previous positions. While they had successfully picked up the movement that Zhou had begun against Lin, they were not adept at creating their own movement. Their attempts to criticize Zhou were petty and showed a lack of understanding about how things worked. By picking on trivial things to criticize, the Gang of Four failed to gain much traction with the people. This was when Mao truly started to see them as a threat to himself. Zhou's work was helping to restore Mao's image, while the Gang of Four was trying to tarnish him. Their downfall on October 6, 1976, a mere month after Mao's death, brought about major celebrations on the streets of Beijing and marked the end of a turbulent political era in China.

Their fall did not amount to a rejection of the Cultural Revolution as such, but it was organized by the new leader, Premier Hua Guofeng, and others who had risen during that period. Significant repudiation of the entire process of change came later, with the return of Deng Xiaoping at the 11th National Congress of the CCP and Hua's gradual loss of authority.

All four were put on trial for treason in 1981. In addition to treason, they were charged with a host of crimes, including causing the death of 34,375 people. To earn greater support, the new government charged the four with aiding and endorsing the persecution of hundreds of thousands of innocent citizens. Wang and Yao confessed, expressing regret at what had happened. Wang Hongwen, who was once thought to be the one chosen to be Mao's successor, was given a life sentence for confessing his crimes, but he was later moved to a hospital in 1986, dying six years later. Yao Wenyuan was given twenty years imprisonment for his role in the Cultural Revolution. He was finally released in 1996 and died nine years later.

Zhang Chunqiao protested that he was innocent of the charges. Jiang Qing, Mao's widow, was the only woman of the group, and she expressed that she had only done what Mao had instructed her to do. Both were given death sentences with a two-year reprieve, though the government never carried them out, instead turning their death sentences into life imprisonment. Zhang was released in 1998 because of a diagnosis of pancreatic cancer, and he died in 2005. Jiang lived under house arrest starting in 1984. Reports say that Mao's widow was diagnosed with throat cancer around 1991. To avoid the pain associated with the disease, she hung herself that same year at the age of 77.