Xu You (died 204) was a strategist serving under the warlord Yuan Shao during the late Han Dynasty period of Chinese history. He was known to be greedy by nature. Xu was a close friend of Cao Cao and during the Battle of Guandu, Xu decided to leave Yuan Shao and join Cao. This was because Shen Pei had informed Yuan that Xu's family had been locked up for charges of corruption. At that time, Xu was suggesting a strategy to Yuan and when Yuan received the news, he sneered at Xu and said, "You still have the cheek to present your strategies in front of me.".