Liu Yizhi (劉禕之) (631 – June 22, 687), courtesy name Ximei (希美), was an official of the Chinese dynasty Tang Dynasty, serving as chancellor during the first reign of Emperor Ruizong. He was initially a trusted advisor of Emperor Ruizong's powerful mother Empress Dowager Wu (later known as Wu Zetian), but later offended her by suggesting privately that she should return imperial powers to Emperor Ruizong, and in 687, she ordered him to commit suicide.
Liu Yizhi was born in 631, during the reign of Emperor Taizong of Tang. His grandfather Liu Xingzong (劉興宗) had served as an army officer during Chen Dynasty, and his father Liu Ziyi (劉子翼) was an official and scholar of renown during Sui Dynasty and the early Tang Dynasty, dying early in the reign of Emperor Taizong's son Emperor Gaozong.
Liu Yizhi himself was said to be literarily talented, and his reputation was compared to contemporaries Meng Lizhen (孟利貞), Gao Zhizhou, and Guo Zhengyi. Eventually, all four were retained to be imperial scholars at the Zhaowen Pavilion (昭文館).
During Emperor Gaozong's Shangyuan 上元 era (674-676), Liu Yizhi was made an imperial chronicler, and a scholar at Hongwen Pavilion (弘文館). He and several colleagues also known for literary talent—Yuan Wanqing (元萬頃), Fan Lübing, Miao Chuke (苗楚客), Zhou Simao (周思茂), and Han Chubin (韓楚賓) -- were asked to serve as advisors to Emperor Gaozong's powerful wife Empress Wu (later known as Wu Zetian), and they wrote a number of works on her behalf, including the Biographies of Notable Women (列女傳), Guidelines for Imperial Subjects (臣軌), and New Teachings for Official Staff Members (百僚新誡). Collectively, they became known as the "North Gate Scholars" (北門學士), because they served inside the palace, which was to the north of the imperial government buildings, and Empress Wu sought advice from them to divert the powers of the chancellors. At that time, both he and his brother Liu Yizhi (劉懿之, note different character) served in government, a fact that impressed many people.