Yue Yi (Traditional Chinese: 樂毅, Simplified Chinese: 乐毅) was an officer of the State of Yan during the Warring State period, also known as Lord Guojun. He was the son of the prime minister of the small nation of Zhongshan, but when Zhongshan was destroyed by Zhao's King Wuling, he was forced to wander from country to country. His talents were recognized by Yan's King Zhao, and he was made a minister. He served with great skill and helped forge the alliance with the nations of Zhao, Wei, Chu, Han and Qin against the threat posed by Qi. He led the allied armies and crushed the Qi forces. The cruel King of Qi was driven away, and, except for two cities, the entire territory of Qi was brought under control. Soon thereafter, King Zhao suddenly died. Due to the scheming of Tian Dan of Qi, King Hui was suspected of involvement in the death and was exiled to Zhao. He left the service of King Zhao on amicable terms but continued to spend time there, and became an important figure in both Zhao and Yan.
Yue Yi is one of the 32 historical figures who appear as special characters in the video game Romance of the Three Kingdoms XI by Koei. In the Chinese classical novel Romance of the Three Kingdoms, Zhuge Liang often compares himself with Yue Yi and Guan Zhong.