Li Yuanji (603 – July 2, 626), formally Prince La of Chao, more commonly known by the title of Prince of Qi, nickname Sanhu, is an imperial prince of the Chinese Tang Dynasty.

He is a son of the dynasty's founder Emperor Gaozu of Tang (Li Yuan), and in the intense rivalry that develops between his older brothers Li Jiancheng the Crown Prince and Li Shimin the Prince of Qin, he sides with Li Jiancheng and often advocates drastic actions against Li Shimin, including assassination.

In 626, Li Shimin, fearing that Li Jiancheng and Li Yuanji are about to kill him, lays an ambush for them at Xuanwu Gate outside the palace and kills them.

Li Shimin then effectively forces Emperor Gaozu to yield the throne to him (as Emperor Taizong).