Zeng Guofan (traditional Chinese: 曾國藩; simplified Chinese: 曾国藩; pinyin: Zēng Guófān;Wade–Giles: Tseng Kuo-fan, Styled Bóhán 伯函 and variably Díshēng 滌生; Posthumous name: Wenzheng 文正; created Marquis Yiyong of the First Class 一等毅勇侯, 世襲罔替) (November 21, 1811 – March 12, 1872) was an eminent Han Chinese official, military general, and devout Confucian scholar of the late Qing Dynasty in China.

Zeng raised the Xiang Army to fight effectively against the Taiping Rebellion and restored the stability of Qing Dynasty along with other prominent figures, including Zuo Zongtang and Li Hongzhang, setting the scene for the era later known as the "Tongzhi Restoration"（同治中兴）. He was known for his strategic perception, administrative skill and noble personality on Confucianist practice, but also sometimes for his ruthlessness on the execution of his policies. Zeng also exemplified loyalty in an era of chaos, but is also regarded as a pre-cursor to the rise of warlordism.

Born as a native of Xiangxiang (湘乡), Hunan, in 1811, Zeng Zicheng (曾子城) was the grandson of Zeng Yuping, a prosperous farmer with social and political ambitions. As a youth, Zeng was notorious for living drunkenly and even experimenting with opium; choices he would later renounce as he became an ardent military man. He studied in Yuelu Academy in Changsha. He passed the prefectural examination in 1833, only a year after his father Zeng Linshu (zi Zhuting). He passed the provincial examination a year later, and by 1838, at age 27, he had successfully passed the metropolitan examinations, a prestigious achievement in China. He had earned the Jinshi degree, the highest level in the civil service examinations, which led to his appointment to the Hanlin Academy, a body of outstanding Chinese literary scholars who performed literary tasks for the imperial court. It was at Hanlin where he changed his name to Zeng Guofan, which sounded more prestigious. Zeng served in Beijing for more than 13 years, and remained devoted to the interpretation of the Confucian Classics. He moved relatively quickly up the ranks by his teacher Manchu statesman Mujangga, advancing to 2nd-Pin in five years.

In 1843, he was appointed chief literary examiner in the province of Sichuan, and six years later was made Senior Deputy Secretary of the Board of Rites (禮部侍郎). When holding the office of Military Examiner (1851) he was compelled by the death of his mother to retire to his native district for the regulation mourning, which is technically supposed to last three years. At this time the Taiping rebels were overrunning Hunan in their conquering career, and had possessed themselves of the cities and strongholds on both shores of the Yangtze River. By a special decree, Zeng was ordered to assist the governor of the province in raising a volunteer force, and, on his own initiative, he built a fleet of war junks, with which he attacked the rebels. This force eventually became known as Zeng's famous Xiang Army. In his first engagement he was defeated, but his lieutenants were more successful. They recovered the capital, Changsha, and destroyed the rebel fleet. Following up these victories of his subordinates, Zeng recaptured Wuchang and Hanyang, near Hankow, and was rewarded for his success by being appointed vice president of the Board of War.

In 1853, other triumphs led to his being made a baturu (a Manchu order for rewarding military prowess), and to his being decorated with a yellow riding jacket. Meanwhile, in his absence, the rebels retook Wuchang and burnt the protecting fleet. The tide quickly turned, however, and Zeng succeeded in clearing the country round the Poyang lake, and subsequently in ridding the province of Jiangsu of the enemy. His father died in 1857, and after a brief mourning he was ordered to take supreme command in Zhejiang, and to co-operate with the governor of Fujian in the defence of that province.

Subsequently, the rebels were driven westwards, and Zeng would have started in pursuit had he not been called on to clear the province of Anhui of rebel bands. In 1860, he was appointed Viceroy of Liangjiang (the provinces of Jiangxi, Anhui, and Jiangsu: 两江总督) and Imperial war commissioner. At this time, and for some time previously, he had been fortunate in having the active support of Zuo Zongtang, who at a later period recovered Kashgar for the emperor, and of Li Hongzhang. Like all true leaders of men, he knew how to reward good service, and when occasion offered he appointed the former to the governorship of Zhejiang and the latter to that of Jiangsu. In 1862, he was appointed assistant grand secretary of state. At this time, the Imperial forces, assisted by the "Ever victorious Army," had checked the progress of the rebellion, and Zeng was able to carry out a scheme which he had long formulated of besieging Nanjing, the rebel headquarters. While Charles George Gordon of the Ever victorious army, with the help of Li Hongzhang, was clearing the cities on the lower waters of the Yangtze River, Zeng drew closer his besieging lines around the city.

In July 1864, Nanjing fell into his hands, and he was rewarded with the rank and title of Marquess (of the First Class) Yiyong (毅勇侯) and the right to wear the double eyed peacock's feather (雙眼花翎). He, Zuo Zongtang and Li Hongzhang were called Zeng, Zuo, Li the leaders in suppressing the Rebellion. After the suppression of the Taiping Rebellion, the Nian Rebellion (捻軍起義), closely related to the former movement, broke out in Shandong, and Zeng was sent to quell it.

Success did not, however, always attend him on this campaign, and by Imperial order he was relieved of his command by Li Hongzhang, who in the same way succeeded him in the viceroyalty of Zhili, where, after the Tianjin Massacre (1870), Zeng failed to carry out the wishes of his Imperial master. Instead of the desired policy towards foreigners, Zeng took on a more diplomatic stance. After this rebuff, he retired to his viceroyalty at Nanjing, where he died in 1872 mysteriously in Hong Xiuquan's former mansion.

Zeng was a voluminous writer. His papers addressed to the throne and his literary disquisitions are held in high esteem by the scholars of China, who treasure the edition of his collected works in 156 books, which was edited by Li Hongzhang in 1876, as a memorial of a great and un-corrupt statesman. Zeng enjoyed reading greatly, and held a special interest in the 23 Histories, and other classics. He was also a dedicated poet and a diary author.

Unlike his contemporaries, Zeng was officially married only once, to a woman of the Ouyang family when he was in his late teens. His wife was known to be a capable woman. He had 3 sons and 5 daughters with her, and two of his eldest children died young. His eldest son, Zeng Jize, who inherited his title of First Class Marquess, went on to become a famous diplomat in late Qing history. His younger brother, Zeng Guoquan, was an ambitious general in the Xiang Army. He was later appointed Viceroy of Liangjiang (the provinces of Jiangxi, Anhui, and Jiangsu: 两江总督) in 1884.

Zeng Guofan's legacy in history is twofold. On the one hand he is criticized as a staunchly conservative traitor, but on the other he is seen as a hero in preserving order and stability. Many in China and abroad admire his ability to successfully survive in the ruthless late Qing bureaucracy. Some have blamed Zeng for all the civilian losses and damages done during the Taiping Rebellion, while others criticize him for being too friendly with certain foreign ideas.

Since the Cultural Revolution, criticism of Zeng gradually began to disappear. Chinese author Tang Haoming published in 1992 his three-book trilogy Zeng Guofan, a novelization of Zeng's life during and after the Taiping Rebellion. This trilogy characterized Zeng as a common person, but had adopted a much more positive view of Zeng. Both Mao Zedong and Chiang Kai-shek have praised Zeng's ability in military and political affairs. Especially in recent years, Zeng Guofan's life and his works have been the topic of many new publications. Zeng's leadership and military skills had been used by many as a new field of thought aiding in business or bureaucratic dealings.