Li Fengji (Chinese: 李逢吉; 758 – February 27, 835), courtesy name Xuzhou (虛舟), formally Duke Cheng of Zheng (鄭成公) or Duke Cheng of Liang (涼成公), was an official of the Chinese dynasty Tang Dynasty, serving as a chancellor during the reigns of Emperor Xianzong, Emperor Xianzong's son Emperor Muzong, and grandson Emperor Jingzong. He was portrayed by traditional accounts as full of machinations against his political opponents.
Li Fengji was born in 758, during the reign of Emperor Suzong. His family was part of the Li clan of Longxi — which was descended from Li Gao the founder of the Western Liang state during the Sixteen Kingdoms period, as the Tang Dynasty imperial clan was, but considered distant enough from the imperial lineage that he was not considered part of the imperial clan. After Li Gao, Li Fengji's family traced its ancestry to a line of officials of Jin Dynasty (265-420), Northern Wei, Northern Qi, Sui Dynasty, and Tang, although Li Fengji's grandfather Li Yan (李顏) and father Li Guiqi (李歸期) were both listed without offices.
As Li Yan was chronically ill and Li Fengji tended to him, Li Fengji studied the medical books of the time and became knowledgeable in medicine. After Li Fengji passed the imperial examinations, the general Fan Xichao (范希朝) invited him to serve as a scribe on his staff when Fan served as the military governor (Jiedushi) of Zhenwu Circuit (振武, headquartered in modern Hohhot, Inner Mongolia). Fan subsequently recommended Li Fengji to then-reigning Emperor Dezong (Emperor Suzong's grandson), and Li Fengji was made a Zuo Shiyi (左拾遺), a low-level consultant at the examination bureau of government (門下省, Menxia Sheng). He was later promoted to Zuo Bujue (左補闕), also consultant at the examination bureau, and then made an imperial censor with the title Shiyushi (侍御史). He later served as the deputy emissary on a mission to Tufan.