Cheng Ji (?-260) was an officer of Wei and the older brother of Cheng Cui. When Cao Mao's plan to kill Sima Zhao was made clear by Wang Chen, he forced his way into the imperial residence and assassinated Cao Mao at the orders of Jia Chong. When Cao Mao's advisers were all disposed of, he was charged with full responsibility for the murder of Cao Mao and then killed so that he did not talk.