Yang Yi (died 235), style name Weigong (威公), was a minister of Shu Han during the Three Kingdoms period of Chinese history. He hailed from Xiangyang and was originally a subject of Cao Wei and later defected to Guan Yu, who sent him to Liu Bei. Liu Bei liked Yang Yi very much after meeting him for the first time and kept him by his side by naming him as the Left General Commanding Officer (左將軍兵曹掾), and after becoming an emperor, Yang Yi was made the Imperial Secretariat (尚書). The Imperial Secretariat was responsible for drafting of imperial edicts; receiving instructions from the highest levels of the government; on occasion they may serve to investigate cases of impeachment or accusations. The Prefect Imperial Secretariat earned a salary of one thousand shi.
Yang Yi participated in the Northern Expeditions of Shu under the command of the strategist Zhuge Liang. He and Wei Yan did not get along well, and it was only the command of Zhuge Liang that kept them from fighting one another outright.
When Zhuge Liang died during his final campaign against Cao Wei, Yang Yi and Wei Yan conflicted on whether to follow Zhuge's orders to retreat. Their disagreement finally broke out into a full-fledged battle, which Yang Yi eventually won. He also slew Wei Yan's entire family shortly after.
Yang Yi was later expelled from the court for complaining about his current rank. He was later jailed for his libelous criticism of Shu Han, and committed suicide in prison.