Cao Zhi (pronunciation^ⓘ; Chinese: 曹植; 192 – 27 December 232), courtesy name Zijian (Chinese: 子建), posthumously known as Prince Si of Chen (陈思王), was a prince of the state of Cao Wei in the Three Kingdoms period of China, and an accomplished poet in his time. His style of poetry, greatly revered during the Jin dynasty and Southern and Northern Dynasties, came to be known as the Jian'an style.

Cao Zhi was a son of Cao Cao, a warlord who rose to power towards the end of the Eastern Han dynasty and laid the foundation for the state of Cao Wei. As Cao Zhi once engaged his elder brother Cao Pi in a power struggle to succeed their father, he was ostracised by his victorious brother after the latter became the emperor and established the Cao Wei state. In his later life, Cao Zhi was not allowed to meddle in politics, despite his many petitions to seek office.

Born in 192, Cao Zhi was the third son of the warlord Cao Cao and Lady Bian. According to the Records of the Three Kingdoms (Sanguozhi), Cao Zhi could recite the Shi Jing, Analects and more than ten thousand verses worth of poems before he even turned 20. His literary talent made him a favorite son of Cao Cao in the early stage of his life. He married Lady Cui of the Cui clan of Qinghe, a niece of Cui Yan.

However, Cao Zhi was an impetuous man with little self-discipline. He was also a heavy drinker. On the other hand, his elder brother Cao Pi knew how to act at the right times. Cao Pi also enjoyed a much closer relationship to the servants and subjects around Cao Cao, and they spoke well of him. In 217, Cao Cao eventually picked Cao Pi to succeed himself. This further aggravated Cao Zhi's already eccentric behaviour. He once rode his chariot along the road reserved for the emperor and through the Sima Gate (司马门), the front gate of the palace. This infuriated his father, who had the chariot driver executed.

Cao Zhi's wife, Lady Cui, was caught by Cao Cao wearing clothes that were too extravagant and superior to her status, violating the law. As punishment she was forced to commit suicide. She was dressed as Crown Princess (consort of the Crown Prince), which was seen as an affront as the succession discussion had ended in favor of Cao Pi as Crown Prince, so she was killed to prevent any further opposition.

Having chosen a successor, Cao Cao took measures to undermine other contestants. He did this by executing Yang Xiu, a chief adviser to Cao Zhi. This greatly unsettled Cao Zhi, but failed to jolt him back to his senses. On the contrary, he sank further into his drunken habits. In 219, Cao Cao's cousin and leading general Cao Ren was besieged at the fortress at Fancheng (樊城; present-day Fancheng District, Hubei) by Guan Yu. Cao Cao named Cao Zhi to lead a relief force to the rescue, in the hope that the task would instil into the latter a sense of responsibility. However, Cao Zhi was so drunk that he could not come forth to take the order. Cao Cao then gave up on this son.

Within months, Cao Cao died. One of the first things Cao Pi did was to do away with Ding Yi (丁儀) and Ding Yì (丁廙), two firm supporters of Cao Zhi. He also sent Cao Zhi, along with the other brothers, away from the capital to a country estate exiling them into the countryside, and prohibited them from taking part in central political issues.

Prospects for Cao Zhi did not improve after Cao Pi died in June 226. He wrote to the second Wei emperor, his nephew Cao Rui, many times, seeking a position to apply his talents. In 232, he even sought a private meeting with Cao Rui to discuss politics. However, Cao Rui probably still considered him a threat to the throne and declined all the offers.