Yue Yi 樂毅 was a general of the state of Yan 燕 during the Warring States period 戰國 (5th cent.-221 BCE). Yue Yi originated in Zhongshan 中山 and was the son of Yue Yang 樂羊, a general serving the state of Wei 魏.
Yue Yi first served the state of Zhao 趙 but left during the internal unrest and entered the service of Wei. When he heard that King Zhao of Yan 燕昭王 (r. 311-279) was looking for able advisors to support him in his planned campaign against the state of Qi 齊, Yue Yi entered the service of Yan and was appointed vice minister (yaqing 亞卿). The campaign was carefully planned because Qi was considered a powerful enemy. Yue Yi managed to create a joint army with troops of Zhao, Chu, Wei, Qin 秦 and Han 韓.
In 284, the army was finally sent out the the battlefield, Yue Yi as the highest commander of the joint forces. In the first battle west of River Ji 濟 the troops of Qi were defeated. Yue Yi sent home the other armies, and with the troops of Yan alone, he attacked the capital of Qi, Linzi 臨淄. King Zhao traveled to the battlefield, inspected the troops, and rewarded Yue Yi with the fief of Chang 昌. In the following months the whole west of Qi was conquered, except two strongholds, Jimo 即墨 and Ju 莒.
When King Zhao died, frictions opened between his successor, King Hui 燕惠王 (r. 278-272), and Yue Yi. Tian Dan 田單, a general of Qi, used this chance to recover the lost territory. When a messenger came from Yan to call back Yue Yi, he feared execution and fled to Zhao, where he was welcomed and enfeoffed as Lord Wangzhu 望諸君, with the fief of Guanjin 觀津. Left alone by their general, the armies of Yan were wiped out by the recovering forces of Qi. King Hui begged for pardon with Yue Yi and asked him to reenter his service. Yue accepted the pardon and from then on served as chief minister for visitors (keqing 客卿) in the states of Zhao and Yan. He died in Zhao, and his son Yue Jian 樂閒 inherited the fief of Chang in Yan.