The conquest of Wu by Jin was a military campaign launched by the Jin dynasty against the state of Wu from late 279 to mid 280 at the end of the Three Kingdoms period of China. The campaign, which started in December 279 or January 280, concluded with complete victory for the Jin dynasty on 1 May 280 when the Wu emperor Sun Hao surrendered. After the campaign, the Jin emperor Sima Yan (Emperor Wu) changed the era name of his reign from "Xianning" to "Taikang". Hence, the campaign has also been referred to as the Taikang campaign.

The campaign is significant in pre-1911 Chinese military history as it not only ended the chaos of the Three Kingdoms period and reunified China under the Jin dynasty, but was also the first successful large-scale military operation in Chinese history that involved a massive invasion force crossing the Yangtze. Among other aspects, its multi-directional approach, invasions by both land and water, and the sending of a naval fleet downstream along the Yangtze, have had strong influences on subsequent battles in Chinese military history.

Following the end of the Eastern Han dynasty in 220, three contending states emerged in China and fought for control over the territories of the former Han Empire. Among the three, Wei was the most powerful one in terms of military prowess, economic resources, manpower and geographical size. The other two, Shu and Wu, reestablished their alliance against Wei in 223.

From as early as 262, the Wei regent Sima Zhao had already started planning for the conquests of Wei's two rival states. He decided to attack Shu first because an invasion of Wu required costly and labour-intensive preparations such as constructing naval vessels and opening up waterways for the vessels. He also pointed out that if Wei managed to conquer Shu, they could make use of Shu's geographical advantage by sending a naval fleet downstream from Shu to attack Wu. In the winter of 262, as the Wei government mobilised troops from the various provinces for the Shu invasion, they also put Tang Zi in charge of overseeing the construction of warships in preparation for a future invasion of Wu.

In early 266, about two years after the surrender and end of Shu, Sima Zhao's son and successor Sima Yan usurped the throne from the last Wei emperor Cao Huan and established the Jin dynasty to replace Wei. During this time, Sima Yan heeded his advisers' suggestions to win over the Shu people's hearts by showing benevolence and generosity, as well as to induce Wu subjects to defect to Jin by tempting them with rewards and incentives. Among other things, he made the former Shu emperor Liu Shan a duke, and awarded peerages, titles and appointments to numerous former Shu subjects and their descendants, including Luo Xian, Chen Shou, Zhuge Jing, Lü Ya, Fei Gong and Chen Yu.

On 29 April 269, Sima Yan ordered Yang Hu to station at Xiangyang and supervise military affairs in the Jin-controlled territories in Jing Province.

In 264, following the Wu emperor Sun Xiu's death, his nephew Sun Hao came to the throne. In the same year, the Wei regent Sima Zhao sent two former Wu officers Xu Shao (徐紹) and Sun Yu (孫彧), who defected to Wei during the Shouchun rebellion, to deliver a letter to Sun Hao. In the letter, Sima Zhao pointed out that Wu stood no chance against a Wei invasion and told Sun Hao that he would be treated generously if he surrendered.

Around April 265, Sun Hao sent Ji Zhi (紀陟) and Hong Qiu (弘璆) as his emissaries to meet Sima Zhao, and express his desire for Wei and Wu to coexist peacefully. Ji Zhi and Hong Qiu accomplished their diplomatic mission well and even impressed Sima Zhao with their replies to questions from various Wei officials.