Fu Jian (Chinese: 苻堅; 337 – 16 October 385), courtesy name Yonggu (永固) or Wenyu (文玉), also known by his posthumous name as the Emperor Xuanzhao of Former Qin (前秦宣昭帝), was the third monarch of the Di-led Chinese Former Qin dynasty, ruling as Heavenly King. Under his reign, the Former Qin unified Northern China by conquering the Former Yan, Chouchi, Former Liang, and Dai, as well as the Eastern Jin's Yi Province (modern Sichuan and Chongqing), until he was repelled at the Battle of Fei River in 383. Following this defeat, the Former Qin state disintegrated and Fu was assassinated in 385 by Yao Chang, his former subordinate who then founded the Later Qin dynasty. He was considered by traditional histories to be a virtuous and just ruler, who, ironically, by sparing too many of his enemies after defeating them, led to his own downfall.

Fu Jian was born in 337, when the family name was still Pu (蒲), to Fu Xiong (苻雄) and his wife Lady Gou. His grandfather Pu Hong (蒲洪) was a Di chieftain and a major general for Later Zhao, serving under the violent emperor Shi Hu, who did however accord Pu great respect. Later, during Later Zhao's collapse, Pu Hong changed his name to Fu Hong, and planned a conquest of the Guanzhong region, but was poisoned by the general Ma Qiu. He was succeeded by his son, Fu Jian's uncle Fu Jian (317–355) (苻健), who advanced west to conquer the Guanzhong region and the surrounding provinces, and established Former Qin in 351. In this, he was ably assisted by Fu Jian's father Fu Xiong, whom he created the Prince of Donghai. In 354, while on a campaign, Fu Xiong died. As the son of Fu Xiong's wife, Fu Jian inherited the title of Prince of Donghai, even though he had at least one older brother, Fu Fa (苻法), who was created the Prince of Qinghe. Fu Jian developed the reputation of being filial and far-sighted, as well as being knowledgeable and able.

As Fu Jian grew older, he received some military responsibilities under his cousin Fu Sheng, who succeeded Former Qin's founding emperor after his death in 355. In 357, when Yao Xiang (姚襄), a major Qiang chief, attacked Former Qin, hoping to conquer it, Fu Jian was one of the generals who fought him and defeated him, capturing and executing him on the battlefield. Yao Xiang's brother Yao Chang surrendered. Initially, the lead general Fu Huangmei (苻黃眉) the Prince of Guangping wanted to put Yao Chang to death, but Fu Jian interceded, and Yao Chang was spared.

Fu Sheng's reign was one filled with violence, caprice, and cruelty. As he killed official after official in his administration, all of the nobles and officials became fearful of being the next target. A number of officials tried to persuade Fu Jian to overthrow Fu Sheng, and it was in the planning stages that Fu Jian, under the introduction of the official Lü Polou (呂婆樓), met Wang Meng, with whom he immediately developed a friendship. Fu Jian planned to act against Fu Sheng but hesitated, since Fu Sheng was a powerful warrior. However, after news leaked that Fu Sheng had planned to kill Fu Jian and his brother Fu Fa, Fu Jian and Fu Fa took immediate action and attacked the palace while Fu Sheng was in a drunken stupor. Fu Sheng's guards surrendered without a fight, and Fu Jian put Fu Sheng to death and took over the throne. He did not, however, take imperial title as Fu Sheng had, but claimed the title "Heavenly King" (Tian Wang). He posthumously honored his father Fu Xiong as an emperor, and he honored his mother Lady Gou as an empress dowager. His wife Lady Gou was created empress.

At the start of Fu Jian's reign, in addition to Wang Meng, he had several other top advisors—his brothers Fu Fa and Fu Rong the Duke of Yangping, his son Fu Pi the Duke of Changle, and his mother Empress Dowager Gou's lover Li Wei (李威). It was with Li's support that Wang's position became increasingly important, eventually becoming one of prime minister status. This was particularly the case when, around new year 358, Empress Dowager Gou, apprehensive of Fu Fa's growing authority, forced him to commit suicide. Senior officials, mostly of Di ethnicity, were often jealous of Wang, but whatever conflict they engaged with Wang always resulted in Wang's prevailing over them, since Wang was favored by Fu Jian. Wang, with Fu Jian's support, established rule of law throughout the empire, and he even executed the founding emperor's honored but corrupt brother-in-law, Qiang De (強德), despite Fu Jian's desire to pardon Qiang. It was described that the empire was ruled efficiently and justly during this period. Fu Jian was also recorded as having the cruel laws of Fu Sheng's reign and the extravagance. He also encouraged his officials to recommend talented people for posts, and rewarded or punished them based on whether the people they recommended performed their jobs well. It was described that Former Qin officials were therefore all highly competent and responsible.

In 364, Fu Jian conferred titles on Zhang Tianxi, the nominal Jin vassal who was the ruler of Former Liang, making him a Former Qin vassal as well. In late 365, however, Zhang Tianxi disavowed that status and cut off relations with Former Qin.

Later in 364, Fu Sheng's brother Fu Teng the Duke of Ru'nan rebelled, but was captured and executed. Wang, concerned about four other brothers of Fu Sheng (Fu You (苻幼) the Duke of Huai'nan, Fu Liu (苻柳) the Duke of Jin, Fu Sou (苻廋) the Duke of Wei, and Fu Wu (苻武) the Duke of Yan), suggested to Fu Jian to have all of them killed. Fu Jian refused.

Late in 364, Fu Jian tried to restore the early Jin system by permitting the dukes—his brothers, sons, and cousins—to commission their own assistants. However, he cancelled the plans when some of the dukes retained rich merchants to serve as their assistants purely on account of their wealth.