Sima Zhao (211 - 265) is a general, politician and regent of the state of Cao Wei during the Three Kingdoms period of Chinese history He maintains control of Cao Wei, seized by his father Sima Yi and maintained by his older brother Sima Shi, and has himself created the Duke of Jin—the penultimate step before usurpation of the throne, although he will never actually take the throne.

He takes advantage of weakness in Shu Han to the west and attacks it, forcing the surrender of Shu's people.

His military credit helps to set up the plot of overthrowing Cao Wei by his son, Sima Yan, who usurps the Cao Wei throne and proclaims the Jin Dynasty.

After the establishment of Jin, Sima Yan posthumously honors him as Emperor Wen of Jin, with the temple name of Taizu.

A Chinese idiom involving and inspired by Sima Zhao is one that states, "Everyone on the street knows what's in Sima Zhao's mind," meaning that a person's supposedly hidden intention (in this case, usurping the throne) is so well known that it is not really hidden any more.

It comes from a quote by Cao Mao, fourth emperor of Cao Wei, who launches an unsuccessful uprising against Sima Zhao to try to take back imperial power.