Chinese eunuch who conspired to seize power on the death of Shihuangdi, first emperor of the Qin dynasty (221–207 BCE). His action eventually led to the downfall of the dynasty.

As the chief eunuch to Shihuangdi, Zhao Gao handled all the emperor's communications with the outside world, so that he had no difficulty in concealing Shihuangdi's death while on a trip in 210 BCE. The emperor's eldest son was in exile on the northern frontier because he had opposed the measures of the minister Li Si to burn all books as a means of proscribing heterodox thought. The emperor's last orders were contained in a sealed letter to his eldest son, whom he named heir apparent. Fearing that the crown prince, if he succeeded to the throne, would have them dismissed and probably killed, Li and Zhao forged a letter to the prince and his companion Meng Tian, the commander of the army of the north, ordering them to commit suicide. The forgery was not immediately discovered, and the two men died. Li and Zhao hastened to return to the capital with the dead emperor, concealing the malodorous corpse in a wagon load of salt fish attached to the rear of the imperial carriage. The conspirators then forged a decree that called for the emperor's infant son, Hu Hai, to ascend the throne.

Li and Zhao soon turned on one another, and Zhao had Li executed. Rebellions thereupon erupted throughout the country, and the rebels soon marched on the capital. Zhao executed the puppet sovereign and set another man on the throne, whom he also attempted to execute. His plot discovered, Zhao was assassinated as he entered the palace.